Spanish ATLAS Tier-1 &Tier-2 perspective on computing over the next years

CERN Document Server

Gonzalez de la Hoz, Santiago; The ATLAS collaboration

2018-01-01

Since the beginning of the WLCG Project the Spanish ATLAS computer centres have contributed with reliable and stable resources as well as personnel for the ATLAS Collaboration. Our contribution to the ATLAS Tier2s and Tier1s computing resources (disk and CPUs) in the last 10 years has been around 5%, even though the Spanish contribution to the ATLAS detector construction as well as the number of authors are both close to 3%. In 2015 an international advisory committee recommended to revise our contribution according to the participation in the ATLAS experiment. With this scenario, we are optimising the federation of three sites located in Barcelona, Madrid and Valencia, taking into account that the ATLAS collaboration has developed workflows and tools to flexibly use all the resources available to the collaboration, where the Tiered structure is somehow vanishing. In this contribution, we would like to show the evolution and technical updates in the ATLAS Spanish Federated Tier2 and Tier1. Some developments w...

Tier-1 and Tier-2 real-time analysis experience in CMS Data Challenge 2004

CERN Document Server

De Filippis, N; Pierro, A; Silvestris, L; Fanfani, A; Grandi, C; Hernández, J M; Bonacorsi, D; Corvo, M; Fanzago, F

2005-01-01

During the CMS Data Challenge 2004 a real-time analysis was attempted at INFN and PIC Tier-1 and Tier-2s in order to test the ability of the instrumented methods to quickly process the data. Several agents and automatic procedures were implemented to perform the analysis at the Tier-1/2 synchronously with the data transfer from Tier-0 at CERN. The system was implemented in the LCG-2 Grid environment and allowed on-the-fly job preparation and subsequent submission to the Resource Broker as new data came along. Running job accessed data from the Storage Elements via remote file protocol, whenever possible, or copying them locally with replica manager commands. Details of the procedures adopted to run the analysis jobs and the expected results are described. An evaluation of the ability of the system to maintain an analysis rate at Tier-1 and Tier-2 comparable with the data transfer rate is also presented. The results on the analysis timeline, the statistics of submitted jobs, the overall efficiency of the GRID ...

A Tiered Model for Linking Students to the Community

Science.gov (United States)

Meyer, Laura Landry; Gerard, Jean M.; Sturm, Michael R.; Wooldridge, Deborah G.

2016-01-01

A tiered practice model (introductory, pre-internship, and internship) embedded in the curriculum facilitates community engagement and creates relevance for students as they pursue a professional identity in Human Development and Family Studies. The tiered model integrates high-impact teaching practices (HIP) and student engagement pedagogies…

Pre evaluation for heat balance of prototype sodium cooled fast reactor

International Nuclear Information System (INIS)

Han, Ji Woong; Kim, De Hee; Yoon, Jung; Kim, Eui Kwang; Lee, Tae Ho

2012-01-01

Under the long term advanced SFR R and D plan, the design of prototype reactor has been carried out toward the construction of the prototype SFR plant by 2028. The R and D efforts in fluid system design will be focused on developing a prototype design of primary heat transport system(PHTS), intermediate heat transport system (IHTS), decay heat removal system(DHRS), steam generation system(SGS), and related auxiliary system design for a prototype reactor as shown in Fig. 1. In order to make progress system design, top tier requirements for prototype reactor related to design parameters of NSSS and BOP should be decided at first. The top tier requirement includes general design basis, capacity and characteristics of reactor, various requirements related to safety, performance, securities, economics, site, and etc.. Extensive discussion has been done within Korea Atomic Energy Research Institute(KAERI) for the decision of top tier requirements of the prototype reactor. The core outlet temperature, which should be described as top tier requirements, is one of the critical parameter for system design. The higher core exit temperature could contribute to increase the plant efficiency. However, it could also contribute to decrease the design margin for structure and safety. Therefore various operating strategies based on different core outlet temperatures should be examined and evaluated. For the prototype reactor two core outlet temperatures are taken into accounted. The lower temperature is for the operation condition and the higher temperature is for the system design and licensing process of the prototype reactor. In order to evaluate the operability of prototype reactor designed based on higher temperature, the heat balance calculations have been performed at different core outlet temperature conditions. The electrical power of prototype reactor was assumed to be 100MWe and reference operating conditions were decided based on existing available data. The

Experience building and operating the CMS Tier-1 computing centres

Science.gov (United States)

Albert, M.; Bakken, J.; Bonacorsi, D.; Brew, C.; Charlot, C.; Huang, Chih-Hao; Colling, D.; Dumitrescu, C.; Fagan, D.; Fassi, F.; Fisk, I.; Flix, J.; Giacchetti, L.; Gomez-Ceballos, G.; Gowdy, S.; Grandi, C.; Gutsche, O.; Hahn, K.; Holzman, B.; Jackson, J.; Kreuzer, P.; Kuo, C. M.; Mason, D.; Pukhaeva, N.; Qin, G.; Quast, G.; Rossman, P.; Sartirana, A.; Scheurer, A.; Schott, G.; Shih, J.; Tader, P.; Thompson, R.; Tiradani, A.; Trunov, A.

2010-04-01

The CMS Collaboration relies on 7 globally distributed Tier-1 computing centres located at large universities and national laboratories for a second custodial copy of the CMS RAW data and primary copy of the simulated data, data serving capacity to Tier-2 centres for analysis, and the bulk of the reprocessing and event selection capacity in the experiment. The Tier-1 sites have a challenging role in CMS because they are expected to ingest and archive data from both CERN and regional Tier-2 centres, while they export data to a global mesh of Tier-2s at rates comparable to the raw export data rate from CERN. The combined capacity of the Tier-1 centres is more than twice the resources located at CERN and efficiently utilizing this large distributed resources represents a challenge. In this article we will discuss the experience building, operating, and utilizing the CMS Tier-1 computing centres. We will summarize the facility challenges at the Tier-1s including the stable operations of CMS services, the ability to scale to large numbers of processing requests and large volumes of data, and the ability to provide custodial storage and high performance data serving. We will also present the operations experience utilizing the distributed Tier-1 centres from a distance: transferring data, submitting data serving requests, and submitting batch processing requests.

Experience building and operating the CMS Tier-1 computing centres

International Nuclear Information System (INIS)

Albert, M; Bakken, J; Huang, Chih-Hao; Dumitrescu, C; Fagan, D; Fisk, I; Giacchetti, L; Gutsche, O; Holzman, B; Bonacorsi, D; Grandi, C; Brew, C; Jackson, J; Charlot, C; Colling, D; Fassi, F; Flix, J; Gomez-Ceballos, G; Hahn, K; Gowdy, S

2010-01-01

The CMS Collaboration relies on 7 globally distributed Tier-1 computing centres located at large universities and national laboratories for a second custodial copy of the CMS RAW data and primary copy of the simulated data, data serving capacity to Tier-2 centres for analysis, and the bulk of the reprocessing and event selection capacity in the experiment. The Tier-1 sites have a challenging role in CMS because they are expected to ingest and archive data from both CERN and regional Tier-2 centres, while they export data to a global mesh of Tier-2s at rates comparable to the raw export data rate from CERN. The combined capacity of the Tier-1 centres is more than twice the resources located at CERN and efficiently utilizing this large distributed resources represents a challenge. In this article we will discuss the experience building, operating, and utilizing the CMS Tier-1 computing centres. We will summarize the facility challenges at the Tier-1s including the stable operations of CMS services, the ability to scale to large numbers of processing requests and large volumes of data, and the ability to provide custodial storage and high performance data serving. We will also present the operations experience utilizing the distributed Tier-1 centres from a distance: transferring data, submitting data serving requests, and submitting batch processing requests.

Development of Two-Tier Diagnostic Test Pictorial-Based for Identifying High School Students Misconceptions on the Mole Concept

Science.gov (United States)

Siswaningsih, W.; Firman, H.; Zackiyah; Khoirunnisa, A.

2017-02-01

The aim of this study was to develop the two-tier pictorial-based diagnostic test for identifying student misconceptions on mole concept. The method of this study is used development and validation. The development of the test Obtained through four phases, development of any items, validation, determination key, and application test. Test was developed in the form of pictorial consisting of two tier, the first tier Consist of four possible answers and the second tier Consist of four possible reasons. Based on the results of content validity of 20 items using the CVR (Content Validity Ratio), a number of 18 items declared valid. Based on the results of the reliability test using SPSS, Obtained 17 items with Cronbach’s Alpha value of 0703, the which means that items have accepted. A total of 10 items was conducted to 35 students of senior high school students who have studied the mole concept on one of the high schools in Cimahi. Based on the results of the application test, student misconceptions were identified in each label concept in mole concept with the percentage of misconceptions on the label concept of mole (60.15%), Avogadro’s number (34.28%), relative atomic mass (62, 84%), relative molecule mass (77.08%), molar mass (68.53%), molar volume of gas (57.11%), molarity (71.32%), chemical equation (82.77%), limiting reactants (91.40%), and molecular formula (77.13%).

Analysis facility infrastructure (Tier-3) for ATLAS experiment

International Nuclear Information System (INIS)

Gonzalez de la Hoz, S.; March, L.; Ros, E.; Sanchez, J.; Amoros, G.; Fassi, F.; Fernandez, A.; Kaci, M.; Lamas, A.; Salt, J.

2008-01-01

In the ATLAS computing model the tiered hierarchy ranged from the Tier-0 (CERN) down to desktops or workstations (Tier-3). The focus on defining the roles of each tiered component has evolved with the initial emphasis on the Tier-0 and Tier-1 definition and roles. The various LHC (Large Hadron Collider) projects, including ATLAS, then evolved the tiered hierarchy to include Tier-2's (Regional centers) as part of their projects. Tier-3 centres, on the other hand, have been defined as whatever an institution could construct to support their Physics goals using institutional and otherwise leveraged resources and therefore have not been considered to be part of the official ATLAS computing resources. However, Tier-3 centres are going to exist and will have implications on how the computing model should support ATLAS physicists. Tier-3 users will want to access LHC data and simulations and will want to enable their resources to support their analysis and simulation work. This document will define how IFIC (Instituto de Fisica Corpuscular de Valencia), after discussing with the ATLAS Tier-3 task force, should interact with the ATLAS computing model, detail the conditions under which Tier-3 centres can expect some level of support and set reasonable expectations for the scope and support of ATLAS Tier-3 sites. (orig.)

Regulatory Compliance in Multi-Tier Supplier Networks

Science.gov (United States)

Goossen, Emray R.; Buster, Duke A.

2014-01-01

Over the years, avionics systems have increased in complexity to the point where 1st tier suppliers to an aircraft OEM find it financially beneficial to outsource designs of subsystems to 2nd tier and at times to 3rd tier suppliers. Combined with challenging schedule and budgetary pressures, the environment in which safety-critical systems are being developed introduces new hurdles for regulatory agencies and industry. This new environment of both complex systems and tiered development has raised concerns in the ability of the designers to ensure safety considerations are fully addressed throughout the tier levels. This has also raised questions about the sufficiency of current regulatory guidance to ensure: proper flow down of safety awareness, avionics application understanding at the lower tiers, OEM and 1st tier oversight practices, and capabilities of lower tier suppliers. Therefore, NASA established a research project to address Regulatory Compliance in a Multi-tier Supplier Network. This research was divided into three major study efforts: 1. Describe Modern Multi-tier Avionics Development 2. Identify Current Issues in Achieving Safety and Regulatory Compliance 3. Short-term/Long-term Recommendations Toward Higher Assurance Confidence This report presents our findings of the risks, weaknesses, and our recommendations. It also includes a collection of industry-identified risks, an assessment of guideline weaknesses related to multi-tier development of complex avionics systems, and a postulation of potential modifications to guidelines to close the identified risks and weaknesses.

Analysis facility infrastructure (Tier-3) for ATLAS experiment

CERN Document Server

González de la Hoza, S; Ros, E; Sánchez, J; Amorós, G; Fassi, F; Fernández, A; Kaci, M; Lamas, A; Salt, J

2008-01-01

In the ATLAS computing model the tiered hierarchy ranged from the Tier-0 (CERN) down to desktops or workstations (Tier-3). The focus on defining the roles of each tiered component has evolved with the initial emphasis on the Tier-0 and Tier-1 definition and roles. The various LHC (Large Hadron Collider) projects, including ATLAS, then evolved the tiered hierarchy to include Tier-2’s (Regional centers) as part of their projects. Tier-3 centres, on the other hand, have been defined as whatever an institution could construct to support their Physics goals using institutional and otherwise leveraged resources and therefore have not been considered to be part of the official ATLAS computing resources. However, Tier-3 centres are going to exist and will have implications on how the computing model should support ATLAS physicists. Tier-3 users will want to access LHC data and simulations and will want to enable their resources to support their analysis and simulation work. This document will define how IFIC (Insti...

Three-tier rough superhydrophobic surfaces

International Nuclear Information System (INIS)

Cao, Yuanzhi; Yuan, Longyan; Hu, Bin; Zhou, Jun

2015-01-01

A three-tier rough superhydrophobic surface was fabricated by growing hydrophobic modified (fluorinated silane) zinc oxide (ZnO)/copper oxide (CuO) hetero-hierarchical structures on silicon (Si) micro-pillar arrays. Compared with the other three control samples with a less rough tier, the three-tier surface exhibits the best water repellency with the largest contact angle 161° and the lowest sliding angle 0.5°. It also shows a robust Cassie state which enables the water to flow with a speed over 2 m s"−"1. In addition, it could prevent itself from being wetted by the droplet with low surface tension (mixed water and ethanol 1:1 in volume) which reveals a flow speed of 0.6 m s"−"1 (dropped from the height of 2 cm). All these features prove that adding another rough tier on a two-tier rough surface could futher improve its water-repellent properties. (paper)

A Two-Tier Multiple Choice Questions to Diagnose Thermodynamic Misconception of Thai and Laos Students

Science.gov (United States)

Kamcharean, Chanwit; Wattanakasiwich, Pornrat

The objective of this study was to diagnose misconceptions of Thai and Lao students in thermodynamics by using a two-tier multiple-choice test. Two-tier multiple choice questions consist of the first tier, a content-based question and the second tier, a reasoning-based question. Data of student understanding was collected by using 10 two-tier multiple-choice questions. Thai participants were the first-year students (N = 57) taking a fundamental physics course at Chiang Mai University in 2012. Lao participants were high school students in Grade 11 (N = 57) and Grade 12 (N = 83) at Muengnern high school in Xayaboury province, Lao PDR. As results, most students answered content-tier questions correctly but chose incorrect answers for reason-tier questions. When further investigating their incorrect reasons, we found similar misconceptions as reported in previous studies such as incorrectly relating pressure with temperature when presenting with multiple variables.

Economic Analysis of Symbiotic Light Water Reactor/Fast Burner Reactor Fuel Cycles Proposed as Part of the U.S. Advanced Fuel Cycle Initiative (AFCI)

International Nuclear Information System (INIS)

Williams, Kent Alan; Shropshire, David E.

2009-01-01

A spreadsheet-based 'static equilibrium' economic analysis was performed for three nuclear fuel cycle scenarios, each designed for 100 GWe-years of electrical generation annually: (1) a 'once-through' fuel cycle based on 100% LWRs fueled by standard UO2 fuel assemblies with all used fuel destined for geologic repository emplacement, (2) a 'single-tier recycle' scenario involving multiple fast burner reactors (37% of generation) accepting actinides (Pu,Np,Am,Cm) from the reprocessing of used fuel from the uranium-fueled LWR fleet (63% of generation), and (3) a 'two-tier' 'thermal+fast' recycle scenario where co-extracted U,Pu from the reprocessing of used fuel from the uranium-fueled part of the LWR fleet (66% of generation) is recycled once as full-core LWR MOX fuel (8% of generation), with the LWR MOX used fuel being reprocessed and all actinide products from both UO2 and MOX used fuel reprocessing being introduced into the closed fast burner reactor (26% of generation) fuel cycle. The latter two 'closed' fuel cycles, which involve symbiotic use of both thermal and fast reactors, have the advantages of lower natural uranium requirements per kilowatt-hour generated and less geologic repository space per kilowatt-hour as compared to the 'once-through' cycle. The overall fuel cycle cost in terms of $ per megawatt-hr of generation, however, for the closed cycles is 15% (single tier) to 29% (two-tier) higher than for the once-through cycle, based on 'expected values' from an uncertainty analysis using triangular distributions for the unit costs for each required step of the fuel cycle. (The fuel cycle cost does not include the levelized reactor life cycle costs.) Since fuel cycle costs are a relatively small percentage (10 to 20%) of the overall busbar cost (LUEC or 'levelized unit electricity cost') of nuclear power generation, this fuel cycle cost increase should not have a highly deleterious effect on the competitiveness of nuclear power. If the reactor life cycle

One-tiered vs. two-tiered forecasting of South African seasonal rainfall

CSIR Research Space (South Africa)

Landman, WA

2010-09-01

Full Text Available -tiered Forecasting of South African Seasonal Rainfall Willem A. Landman1, Dave DeWitt2 and Daleen L?tter3 1: Council for Scientific and Industrial Research; WALandman@csir.co.za 2: International Research Institute for Climate and Society; Daved... modelled as fully interacting is called a fully coupled model system. Forecast performance by such systems predicting seasonal rainfall totals over South Africa is compared with forecasts produced by a computationally less demanding two-tiered system...

The CMS experiment workflows on StoRM based storage at Tier-1 and Tier-2 centers

International Nuclear Information System (INIS)

Bonacorsi, D; Bartolome, I Cabrillo; Matorras, F; Gonzalez Caballero, I; Sartirana, A

2010-01-01

Approaching LHC data taking, the CMS experiment is deploying, commissioning and operating the building tools of its grid-based computing infrastructure. The commissioning program includes testing, deployment and operation of various storage solutions to support the computing workflows of the experiment. Recently, some of the Tier-1 and Tier-2 centers supporting the collaboration have started to deploy StoRM based storage systems. These are POSIX-based disk storage systems on top of which StoRM implements the Storage Resource Manager (SRM) version 2 interface allowing for a standard-based access from the Grid. In this notes we briefly describe the experience so far achieved at the CNAF Tier-1 center and at the IFCA Tier-2 center.

Tier-3 Monitoring Software Suite (T3MON) proposal

CERN Document Server

Andreeva, J; The ATLAS collaboration; Klimentov, A; Korenkov, V; Oleynik, D; Panitkin, S; Petrosyan, A

2011-01-01

The ATLAS Distributed Computing activities concentrated so far in the “central” part of the computing system of the experiment, namely the first 3 tiers (CERN Tier0, the 10 Tier1s centres and the 60+ Tier2s). This is a coherent system to perform data processing and management on a global scale and host (re)processing, simulation activities down to group and user analysis. Many ATLAS Institutes and National Communities built (or have plans to build) Tier-3 facilities. The definition of Tier-3 concept has been outlined (REFERENCE). Tier-3 centres consist of non-pledged resources mostly dedicated for the data analysis by the geographically close or local scientific groups. Tier-3 sites comprise a range of architectures and many do not possess Grid middleware, which would render application of Tier-2 monitoring systems useless. This document describes a strategy to develop a software suite for monitoring of the Tier3 sites. This software suite will enable local monitoring of the Tier3 sites and the global vie...

Tiered Approach to Resilience Assessment.

Science.gov (United States)

Linkov, Igor; Fox-Lent, Cate; Read, Laura; Allen, Craig R; Arnott, James C; Bellini, Emanuele; Coaffee, Jon; Florin, Marie-Valentine; Hatfield, Kirk; Hyde, Iain; Hynes, William; Jovanovic, Aleksandar; Kasperson, Roger; Katzenberger, John; Keys, Patrick W; Lambert, James H; Moss, Richard; Murdoch, Peter S; Palma-Oliveira, Jose; Pulwarty, Roger S; Sands, Dale; Thomas, Edward A; Tye, Mari R; Woods, David

2018-04-25

Regulatory agencies have long adopted a three-tier framework for risk assessment. We build on this structure to propose a tiered approach for resilience assessment that can be integrated into the existing regulatory processes. Comprehensive approaches to assessing resilience at appropriate and operational scales, reconciling analytical complexity as needed with stakeholder needs and resources available, and ultimately creating actionable recommendations to enhance resilience are still lacking. Our proposed framework consists of tiers by which analysts can select resilience assessment and decision support tools to inform associated management actions relative to the scope and urgency of the risk and the capacity of resource managers to improve system resilience. The resilience management framework proposed is not intended to supplant either risk management or the many existing efforts of resilience quantification method development, but instead provide a guide to selecting tools that are appropriate for the given analytic need. The goal of this tiered approach is to intentionally parallel the tiered approach used in regulatory contexts so that resilience assessment might be more easily and quickly integrated into existing structures and with existing policies. Published 2018. This article is a U.S. government work and is in the public domain in the USA.

The Legnaro-Padova distributed Tier-2: challenges and results

Science.gov (United States)

Badoer, Simone; Biasotto, Massimo; Costa, Fulvia; Crescente, Alberto; Fantinel, Sergio; Ferrari, Roberto; Gulmini, Michele; Maron, Gaetano; Michelotto, Michele; Sgaravatto, Massimo; Toniolo, Nicola

2014-06-01

The Legnaro-Padova Tier-2 is a computing facility serving the ALICE and CMS LHC experiments. It also supports other High Energy Physics experiments and other virtual organizations of different disciplines, which can opportunistically harness idle resources if available. The unique characteristic of this Tier-2 is its topology: the computational resources are spread in two different sites, about 15 km apart: the INFN Legnaro National Laboratories and the INFN Padova unit, connected through a 10 Gbps network link (it will be soon updated to 20 Gbps). Nevertheless these resources are seamlessly integrated and are exposed as a single computing facility. Despite this intrinsic complexity, the Legnaro-Padova Tier-2 ranks among the best Grid sites for what concerns reliability and availability. The Tier-2 comprises about 190 worker nodes, providing about 26000 HS06 in total. Such computing nodes are managed by the LSF local resource management system, and are accessible using a Grid-based interface implemented through multiple CREAM CE front-ends. dCache, xrootd and Lustre are the storage systems in use at the Tier-2: about 1.5 PB of disk space is available to users in total, through multiple access protocols. A 10 Gbps network link, planned to be doubled in the next months, connects the Tier-2 to WAN. This link is used for the LHC Open Network Environment (LHCONE) and for other general purpose traffic. In this paper we discuss about the experiences at the Legnaro-Padova Tier-2: the problems that had to be addressed, the lessons learned, the implementation choices. We also present the tools used for the daily management operations. These include DOCET, a Java-based webtool designed, implemented and maintained at the Legnaro-Padova Tier-2, and deployed also in other sites, such as the LHC Italian T1. DOCET provides an uniform interface to manage all the information about the physical resources of a computing center. It is also used as documentation repository available to

The Legnaro-Padova distributed Tier-2: challenges and results

International Nuclear Information System (INIS)

Badoer, Simone; Biasotto, Massimo; Fantinel, Sergio

2014-01-01

The Legnaro-Padova Tier-2 is a computing facility serving the ALICE and CMS LHC experiments. It also supports other High Energy Physics experiments and other virtual organizations of different disciplines, which can opportunistically harness idle resources if available. The unique characteristic of this Tier-2 is its topology: the computational resources are spread in two different sites, about 15 km apart: the INFN Legnaro National Laboratories and the INFN Padova unit, connected through a 10 Gbps network link (it will be soon updated to 20 Gbps). Nevertheless these resources are seamlessly integrated and are exposed as a single computing facility. Despite this intrinsic complexity, the Legnaro-Padova Tier-2 ranks among the best Grid sites for what concerns reliability and availability. The Tier-2 comprises about 190 worker nodes, providing about 26000 HS06 in total. Such computing nodes are managed by the LSF local resource management system, and are accessible using a Grid-based interface implemented through multiple CREAM CE front-ends. dCache, xrootd and Lustre are the storage systems in use at the Tier-2: about 1.5 PB of disk space is available to users in total, through multiple access protocols. A 10 Gbps network link, planned to be doubled in the next months, connects the Tier-2 to WAN. This link is used for the LHC Open Network Environment (LHCONE) and for other general purpose traffic. In this paper we discuss about the experiences at the Legnaro-Padova Tier-2: the problems that had to be addressed, the lessons learned, the implementation choices. We also present the tools used for the daily management operations. These include DOCET, a Java-based webtool designed, implemented and maintained at the Legnaro-Padova Tier-2, and deployed also in other sites, such as the LHC Italian T1. DOCET provides an uniform interface to manage all the information about the physical resources of a computing center. It is also used as documentation repository available to

Analisis Tingkat Pemahaman Konsep Siswa Kelas XI IPA Sman 3 Mataram Menggunakan One Tier Dan Two Tier Test Materi Kelarutan Dan Hasil Kali Kelarutan

OpenAIRE

Nabilah, Nabilah; Andayani, Yayuk; Laksmiwati, Dwi

2013-01-01

: The objective of this research was to analyzed conceptual understanding level of XI science grade students of SMAN 3 Mataram by used one-tier and two-tier test in solubility and solubility product subject. One-tier test are examined to XI IPA 4 grade students and two-tier test to XI IPA 5 grade students. The results of conceptual understanding using one-tier test (57,4%) are higher than using two-tier test (21,03%). One-tier test only showed the students's conceptual understanding, whereas ...

Study of trans-uranian incineration in molten salt reactor

International Nuclear Information System (INIS)

Valade, M.

2000-01-01

With the emergence of new options for nuclear power, molten salt reactors are envisaged for waste management. The aim of this thesis is to show how molten salt reactors can help to solve the transuranics issue. Their high versatility regarding to isotopic vector allows to accommodate large fractions of minor actinides as compared to solid fuel system. In this thesis, a neutronics study of molten salt reactors, MSR, has been conducted. For this purpose, two reference systems were considered, TIER1 and AMSTER. In the case of TIER1, an optimisation was made to reach an equilibrium. The analysis of both systems showed the main characteristics of MSR: their link to chemistry and on line reprocessing. In this work, several methods to drive the system to a state of equilibrium have been implemented and compared. During this process the isotopic composition and neutron spectrum, thus the nuclear reaction cross sections, vary tremendously. It is essential to take these evolutions into account in order to accurately estimate the equilibrium state. This has been accomplished inside the multi-recycling procedure we set with ERANOS. A dedicated calculation schema has been realized to simulate superthermal systems with this computation code. These results were checked through a benchmark against other computer codes. Then, with multi-recycling method, several molten salt systems have been compared in order to define the optimal reactor for transuranics incineration. Nevertheless, a final choice can not only be done using only neutronics characteristics since chemistry and thermal-hydraulics constraints are really important for MSR. Moreover, a complete safety study would be required. (author)

Medium-Power Lead-Alloy Reactors: Missions for This Reactor Technology

International Nuclear Information System (INIS)

Todreas, Neil E.; MacDonald, Philip E.; Hejzlar, Pavel; Buongiorno, Jacopo; Loewen, Eric P.

2004-01-01

A multiyear project at the Idaho National Engineering and Environmental Laboratory and the Massachusetts Institute of Technology investigated the potential of medium-power lead-alloy-cooled technology to perform two missions: (1) the production of low-cost electricity and (2) the burning of actinides from light water reactor (LWR) spent fuel. The goal of achieving a high power level to enhance economic performance simultaneously with adoption of passive decay heat removal and modularity capabilities resulted in designs in the range of 600-800 MW(thermal), which we classify as a medium power level compared to the lower [∼100 MW(thermal)] and higher [2800 MW(thermal)] power ratings of other lead-alloy-cooled designs. The plant design that was developed shows promise of achieving all the Generation-IV goals for future nuclear energy systems: sustainable energy generation, low overnight capital cost, a very low likelihood and degree of core damage during any conceivable accident, and a proliferation-resistant fuel cycle. The reactor and fuel cycle designs that evolved to achieve these missions and goals resulted from study of the following key trade-offs: waste reduction versus reactor safety, waste reduction versus cost, and cost versus proliferation resistance. Secondary trade-offs that were also considered were monolithic versus modular design, active versus passive safety systems, forced versus natural circulation, alternative power conversion cycles, and lead versus lead-bismuth coolant.These studies led to a selection of a common modular design with forced convection cooling, passive decay heat removal, and a supercritical CO 2 power cycle for all our reactor concepts. However, the concepts adopt different core designs to optimize the achievement of the two missions. For the low-cost electricity production mission, a design approach based on fueling with low enriched uranium operating without costly reprocessing in a once-through cycle was pursued to achieve a

Assessment of risk to wildlife from ionising radiation: can initial screening tiers be used with a high level of confidence?

International Nuclear Information System (INIS)

Beresford, N A; Barnett, C L; Hosseini, A; Brown, J E; Cailes, C; Copplestone, D; Beaugelin-Seiller, K

2010-01-01

A number of models are being used to assess the potential environmental impact of releases of radioactivity. These often use a tiered assessment structure whose first tier is designed to be highly conservative and simple to use. An aim of using this initial tier is to identify sites of negligible concern and to remove them from further consideration with a high degree of confidence. In this paper we compare the screening assessment outputs of three freely available models. The outputs of these models varied considerably in terms of estimated risk quotient (RQ) and the radionuclide-organism combinations identified as being the most limiting. A number of factors are identified as contributing to this variability: values of transfer parameters (concentration ratios and K d ) used; organisms considered; different input options and how these are utilised in the assessment; assumptions as regards secular equilibrium; geometries and exposure scenarios. This large variation in RQ values between models means that the level of confidence required by users is not achieved. We recommend that the factors contributing to the variation in screening assessments be subjected to further investigation so that they can be more fully understood and assessors (and those reviewing assessment outputs) can better justify and evaluate the results obtained.

Four Tiers

Science.gov (United States)

Moodie, Gavin

2009-01-01

This paper posits a classification of tertiary education institutions into four tiers: world research universities, selecting universities, recruiting universities, and vocational institutes. The distinguishing characteristic of world research universities is their research strength, the distinguishing characteristic of selecting universities is…

INFN Tier-1 Testbed Facility

International Nuclear Information System (INIS)

Gregori, Daniele; Cavalli, Alessandro; Dell'Agnello, Luca; Dal Pra, Stefano; Prosperini, Andrea; Ricci, Pierpaolo; Ronchieri, Elisabetta; Sapunenko, Vladimir

2012-01-01

INFN-CNAF, located in Bologna, is the Information Technology Center of National Institute of Nuclear Physics (INFN). In the framework of the Worldwide LHC Computing Grid, INFN-CNAF is one of the eleven worldwide Tier-1 centers to store and reprocessing Large Hadron Collider (LHC) data. The Italian Tier-1 provides the resources of storage (i.e., disk space for short term needs and tapes for long term needs) and computing power that are needed for data processing and analysis to the LHC scientific community. Furthermore, INFN Tier-1 houses computing resources for other particle physics experiments, like CDF at Fermilab, SuperB at Frascati, as well as for astro particle and spatial physics experiments. The computing center is a very complex infrastructure, the hardaware layer include the network, storage and farming area, while the software layer includes open source and proprietary software. Software updating and new hardware adding can unexpectedly deteriorate the production activity of the center: therefore a testbed facility has been set up in order to reproduce and certify the various layers of the Tier-1. In this article we describe the testbed and the checks performed.

Technology Tiers

DEFF Research Database (Denmark)

Karlsson, Christer

2015-01-01

A technology tier is a level in a product system: final product, system, subsystem, component, or part. As a concept, it contrasts traditional “vertical” special technologies (for example, mechanics and electronics) and focuses “horizontal” feature technologies such as product characteristics...

Proposed Tier 2 Screening Criteria and Tier 3 Field Procedures for Evaluation of Vapor Intrusion (ESTCP Cost and Performance Report)

Science.gov (United States)

2012-08-01

Security Technology Certification Program ETV Environmental Technology Verification GC gas chromatography HGL HydroGeoLogic, Inc . ITRC... Inc . (HGL) for invaluable project support. This page left blank intentionally. 1 1.0 EXECUTIVE SUMMARY 1.1 OBJECTIVES OF THE... NIKE Battery Site PR-58 N. Kingstown, RI Tier 2 Industrial Site Southeast TX Tier 2 Note: * = Tier 2 demonstration not completed due to the

Implementation of Grid Tier 2 and Tier 3 facilities on a Distributed OpenStack Cloud

Science.gov (United States)

Limosani, Antonio; Boland, Lucien; Coddington, Paul; Crosby, Sean; Huang, Joanna; Sevior, Martin; Wilson, Ross; Zhang, Shunde

2014-06-01

The Australian Government is making a AUD 100 million investment in Compute and Storage for the academic community. The Compute facilities are provided in the form of 30,000 CPU cores located at 8 nodes around Australia in a distributed virtualized Infrastructure as a Service facility based on OpenStack. The storage will eventually consist of over 100 petabytes located at 6 nodes. All will be linked via a 100 Gb/s network. This proceeding describes the development of a fully connected WLCG Tier-2 grid site as well as a general purpose Tier-3 computing cluster based on this architecture. The facility employs an extension to Torque to enable dynamic allocations of virtual machine instances. A base Scientific Linux virtual machine (VM) image is deployed in the OpenStack cloud and automatically configured as required using Puppet. Custom scripts are used to launch multiple VMs, integrate them into the dynamic Torque cluster and to mount remote file systems. We report on our experience in developing this nation-wide ATLAS and Belle II Tier 2 and Tier 3 computing infrastructure using the national Research Cloud and storage facilities.

Implementation of Grid Tier 2 and Tier 3 facilities on a Distributed OpenStack Cloud

International Nuclear Information System (INIS)

Limosani, Antonio; Boland, Lucien; Crosby, Sean; Huang, Joanna; Sevior, Martin; Coddington, Paul; Zhang, Shunde; Wilson, Ross

2014-01-01

The Australian Government is making a $AUD 100 million investment in Compute and Storage for the academic community. The Compute facilities are provided in the form of 30,000 CPU cores located at 8 nodes around Australia in a distributed virtualized Infrastructure as a Service facility based on OpenStack. The storage will eventually consist of over 100 petabytes located at 6 nodes. All will be linked via a 100 Gb/s network. This proceeding describes the development of a fully connected WLCG Tier-2 grid site as well as a general purpose Tier-3 computing cluster based on this architecture. The facility employs an extension to Torque to enable dynamic allocations of virtual machine instances. A base Scientific Linux virtual machine (VM) image is deployed in the OpenStack cloud and automatically configured as required using Puppet. Custom scripts are used to launch multiple VMs, integrate them into the dynamic Torque cluster and to mount remote file systems. We report on our experience in developing this nation-wide ATLAS and Belle II Tier 2 and Tier 3 computing infrastructure using the national Research Cloud and storage facilities.

Report on Tier-0 Scaling Tests

CERN Multimedia

M. Branco; L. Goossens; A. Nairz

To get prepared for handling the enormous data rates and volumes during LHC operation, ATLAS is currently running so-called Tier-0 Scaling Tests, which were started beginning of November and will last until Christmas. These tests are carried out in the context of LCG (LHC Computing Grid) Service Challenge 3 (SC3), a joint exercise of CERN IT and the LHC experiments to test the infrastructure of computing, network, and data management, in particular for its architecture, scalabilty and readiness for LHC data taking. ATLAS has adopted a multi-Tier hierarchical model to organise the workflow, with dedicated tasks to be performed at the individual levels in the Tier hierarchy. The Tier-0 centre located at CERN will be responsible for performing a first-pass reconstruction of the data arriving from the Event Filter farm, thus producing Event Summary Data (ESDs), Analysis Object Data (AODs) and event Tags, for processing calibration and alignment information, for archiving both raw and reconstructed data, and for ...

ATLAS Tier-3 within IFIC-Valencia analysis facility

CERN Document Server

Villaplana, M; The ATLAS collaboration; Fernández, A; Salt, J; Lamas, A; Fassi, F; Kaci, M; Oliver, E; Sánchez, J; Sánchez-Martínez, V

2012-01-01

The ATLAS Tier-3 at IFIC-Valencia is attached to a Tier-2 that has 50% of the Spanish Federated Tier-2 resources. In its design, the Tier-3 includes a GRID-aware part that shares some of the features of IFIC Tier-2 such as using Lustre as a file system. ATLAS users, 70% of IFIC users, also have the possibility of analysing data with a PROOF farm and storing them locally. In this contribution we discuss the design of the analysis facility as well as the monitoring tools we use to control and improve its performance. We also comment on how the recent changes in the ATLAS computing GRID model affect IFIC. Finally, how this complex system can coexist with the other scientific applications running at IFIC (non-ATLAS users) is presented.

Identifying tier one key suppliers.

Science.gov (United States)

Wicks, Steve

2013-01-01

In today's global marketplace, businesses are becoming increasingly reliant on suppliers for the provision of key processes, activities, products and services in support of their strategic business goals. The result is that now, more than ever, the failure of a key supplier has potential to damage reputation, productivity, compliance and financial performance seriously. Yet despite this, there is no recognised standard or guidance for identifying a tier one key supplier base and, up to now, there has been little or no research on how to do so effectively. This paper outlines the key findings of a BCI-sponsored research project to investigate good practice in identifying tier one key suppliers, and suggests a scalable framework process model and risk matrix tool to help businesses effectively identify their tier one key supplier base.

26 CFR 1.1446-5 - Tiered partnership structures.

Science.gov (United States)

2010-04-01

... defined in § 1.1446-4(b)(1)). (2) Lower-tier publicly traded partnership. The look through rules of... 26 Internal Revenue 12 2010-04-01 2010-04-01 false Tiered partnership structures. 1.1446-5 Section...-Free Covenant Bonds § 1.1446-5 Tiered partnership structures. (a) In general. The rules of this section...

Reactor operations Brookhaven medical research reactor, Brookhaven high flux beam reactor informal monthly report

International Nuclear Information System (INIS)

Hauptman, H.M.; Petro, J.N.; Jacobi, O.

1995-04-01

This document is the April 1995 summary report on reactor operations at the Brookhaven Medical Research Reactor and the Brookhaven High Flux Beam Reactor. Ongoing experiments/irradiations in each are listed, and other significant operations functions are also noted. The HFBR surveillance testing schedule is also listed

Exercising CMS dataflows and workflows in computing challenges at the SpanishTier-1 and Tier-2 sites

International Nuclear Information System (INIS)

Caballero, J; Colino, N; Peris, A D; G-Abia, P; Hernandez, J M; R-Calonge, F J; Cabrillo, I; Caballero, I G; Marco, R; Matorras, F; Flix, J; Merino, G

2008-01-01

An overview of the data transfer, processing and analysis operations conducted at the Spanish Tier-1 (PIC, Barcelona) and Tier-2 (CIEMAT-Madrid and IFCA-Santander federation) centres during the past CMS CSA06 Computing, Software and Analysis challenge and in preparation for CSA07 is presented

Achieving Tier 4 Emissions in Biomass Cookstoves

Energy Technology Data Exchange (ETDEWEB)

Marchese, Anthony [Colorado State Univ., Fort Collins, CO (United States); DeFoort, Morgan [Colorado State Univ., Fort Collins, CO (United States); Gao, Xinfeng [Colorado State Univ., Fort Collins, CO (United States); Tryner, Jessica [Colorado State Univ., Fort Collins, CO (United States); Dryer, Frederick L. [Princeton Univ., Princeton, NJ (United States); Haas, Francis [Princeton Univ., Princeton, NJ (United States); Lorenz, Nathan [Envirofit International, Fort Collins, CO (United States)

2018-03-13

Previous literature on top-lit updraft (TLUD) gasifier cookstoves suggested that these stoves have the potential to be the lowest emitting biomass cookstove. However, the previous literature also demonstrated a high degree of variability in TLUD emissions and performance, and a lack of general understanding of the TLUD combustion process. The objective of this study was to improve understanding of the combustion process in TLUD cookstoves. In a TLUD, biomass is gasified and the resulting producer gas is burned in a secondary flame located just above the fuel bed. The goal of this project is to enable the design of a more robust TLUD that consistently meets Tier 4 performance targets through a better understanding of the underlying combustion physics. The project featured a combined modeling, experimental and product design/development effort comprised of four different activities: Development of a model of the gasification process in the biomass fuel bed; Development of a CFD model of the secondary combustion zone; Experiments with a modular TLUD test bed to provide information on how stove design, fuel properties, and operating mode influence performance and provide data needed to validate the fuel bed model; Planar laser-induced fluorescence (PLIF) experiments with a two-dimensional optical test bed to provide insight into the flame dynamics in the secondary combustion zone and data to validate the CFD model; Design, development and field testing of a market ready TLUD prototype. Over 180 tests of 40 different configurations of the modular TLUD test bed were performed to demonstrate how stove design, fuel properties and operating mode influences performance, and the conditions under which Tier 4 emissions are obtainable. Images of OH and acetone PLIF were collected at 10 kHz with the optical test bed. The modeling and experimental results informed the design of a TLUD prototype that met Tier 3 to Tier 4 specifications in emissions and Tier 2 in efficiency. The

Exercising CMS dataflows and workflows in computing challenges at the SpanishTier-1 and Tier-2 sites

Energy Technology Data Exchange (ETDEWEB)

Caballero, J; Colino, N; Peris, A D; G-Abia, P; Hernandez, J M; R-Calonge, F J [CIEMAT, Madrid (Spain); Cabrillo, I; Caballero, I G; Marco, R; Matorras, F [IFCA, Santander (Spain); Flix, J; Merino, G [PIC, Barcelona (Spain)], E-mail: jose.hernandez@ciemat.es

2008-07-15

An overview of the data transfer, processing and analysis operations conducted at the Spanish Tier-1 (PIC, Barcelona) and Tier-2 (CIEMAT-Madrid and IFCA-Santander federation) centres during the past CMS CSA06 Computing, Software and Analysis challenge and in preparation for CSA07 is present0008.

76 FR 18260 - Announcement Regarding Pennsylvania Triggering “Off” Tier Four of Emergency Unemployment...

Science.gov (United States)

2011-04-01

... Triggering ``Off'' Tier Four of Emergency Unemployment Compensation 2008 (EUC08). AGENCY: Employment and... ``off'' Tier Four of Emergency Unemployment Compensation 2008 (EUC08). Public Law 111-312 extended... the EUC08 program for qualified unemployed workers claiming benefits in high unemployment states. The...

Distributed Analysis Experience using Ganga on an ATLAS Tier2 infrastructure

International Nuclear Information System (INIS)

Fassi, F.; Cabrera, S.; Vives, R.; Fernandez, A.; Gonzalez de la Hoz, S.; Sanchez, J.; March, L.; Salt, J.; Kaci, M.; Lamas, A.; Amoros, G.

2007-01-01

The ATLAS detector will explore the high-energy frontier of Particle Physics collecting the proton-proton collisions delivered by the LHC (Large Hadron Collider). Starting in spring 2008, the LHC will produce more than 10 Peta bytes of data per year. The adapted tiered hierarchy for computing model at the LHC is: Tier-0 (CERN), Tiers-1 and Tiers-2 centres distributed around the word. The ATLAS Distributed Analysis (DA) system has the goal of enabling physicists to perform Grid-based analysis on distributed data using distributed computing resources. IFIC Tier-2 facility is participating in several aspects of DA. In support of the ATLAS DA activities a prototype is being tested, deployed and integrated. The analysis data processing applications are based on the Athena framework. GANGA, developed by LHCb and ATLAS experiments, allows simple switching between testing on a local batch system and large-scale processing on the Grid, hiding Grid complexities. GANGA deals with providing physicists an integrated environment for job preparation, bookkeeping and archiving, job splitting and merging. The experience with the deployment, configuration and operation of the DA prototype will be presented. Experiences gained of using DA system and GANGA in the Top physics analysis will be described. (Author)

The effect of a three-tier formulary on antidepressant utilization and expenditures.

Science.gov (United States)

Hodgkin, Dominic; Parks Thomas, Cindy; Simoni-Wastila, Linda; Ritter, Grant A; Lee, Sue

2008-06-01

Health plans in the United States are struggling to contain rapid growth in their spending on medications. They have responded by implementing multi-tiered formularies, which label certain brand medications 'non-preferred' and require higher patient copayments for those medications. This multi-tier policy relies on patients' willingness to switch medications in response to copayment differentials. The antidepressant class has certain characteristics that may pose problems for implementation of three-tier formularies, such as differences in which medication works for which patient, and high rates of medication discontinuation. To measure the effect of a three-tier formulary on antidepressant utilization and spending, including decomposing spending allocations between patient and plan. We use claims and eligibility files for a large, mature nonprofit managed care organization that started introducing its three-tier formulary on January 1, 2000, with a staggered implementation across employer groups. The sample includes 109,686 individuals who were continuously enrolled members during the study period. We use a pretest-posttest quasi-experimental design that includes a comparison group, comprising members whose employer had not adopted three-tier as of March 1, 2000. This permits some control for potentially confounding changes that could have coincided with three-tier implementation. For the antidepressants that became nonpreferred, prescriptions per enrollee decreased 11% in the three-tier group and increased 5% in the comparison group. The own-copay elasticity of demand for nonpreferred drugs can be approximated as -0.11. Difference-in-differences regression finds that the three-tier formulary slowed the growth in the probability of using antidepressants in the post-period, which was 0.3 percentage points lower than it would have been without three-tier. The three-tier formulary also increased out-of-pocket payments while reducing plan payments and total spending

The US-CMS Tier-1 Center Network Evolving toward 100Gbps

International Nuclear Information System (INIS)

Bobyshev, A; DeMar, P

2011-01-01

Fermilab hosts the US Tier-1 Center for the LHC's Compact Muon Collider (CMS) experiment. The Tier-1s are the central points for the processing and movement of LHC data. They sink raw data from the Tier-0 at CERN, process and store it locally, and then distribute the processed data to Tier-2s for simulation studies and analysis. The Fermilab Tier-1 Center is the largest of the CMS Tier-1s, accounting for roughly 35% of the experiment's Tier-1 computing and storage capacity. Providing capacious, resilient network services, both in terms of local network infrastructure and off-site data movement capabilities, presents significant challenges. This article will describe the current architecture, status, and near term plans for network support of the US-CMS Tier-1 facility.

The analysis for inventory of experimental reactor high temperature gas reactor type

International Nuclear Information System (INIS)

Sri Kuntjoro; Pande Made Udiyani

2016-01-01

Relating to the plan of the National Nuclear Energy Agency (BATAN) to operate an experimental reactor of High Temperature Gas Reactors type (RGTT), it is necessary to reactor safety analysis, especially with regard to environmental issues. Analysis of the distribution of radionuclides from the reactor into the environment in normal or abnormal operating conditions starting with the estimated reactor inventory based on the type, power, and operation of the reactor. The purpose of research is to analyze inventory terrace for Experimental Power Reactor design (RDE) high temperature gas reactor type power 10 MWt, 20 MWt and 30 MWt. Analyses were performed using ORIGEN2 computer code with high temperatures cross-section library. Calculation begins with making modifications to some parameter of cross-section library based on the core average temperature of 570 °C and continued with calculations of reactor inventory due to RDE 10 MWt reactor power. The main parameters of the reactor 10 MWt RDE used in the calculation of the main parameters of the reactor similar to the HTR-10 reactor. After the reactor inventory 10 MWt RDE obtained, a comparison with the results of previous researchers. Based upon the suitability of the results, it make the design for the reactor RDE 20MWEt and 30 MWt to obtain the main parameters of the reactor in the form of the amount of fuel in the pebble bed reactor core, height and diameter of the terrace. Based on the main parameter or reactor obtained perform of calculation to get reactor inventory for RDE 20 MWT and 30 MWT with the same methods as the method of the RDE 10 MWt calculation. The results obtained are the largest inventory of reactor RDE 10 MWt, 20 MWt and 30 MWt sequentially are to Kr group are about 1,00E+15 Bq, 1,20E+16 Bq, 1,70E+16 Bq, for group I are 6,50E+16 Bq, 1,20E+17 Bq, 1,60E+17 Bq and for groups Cs are 2,20E+16 Bq, 2,40E+16 Bq, 2,60E+16 Bq. Reactor inventory will then be used to calculate the reactor source term and it

38 CFR 36.4318 - Servicer tier ranking-temporary procedures.

Science.gov (United States)

2010-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Servicer tier ranking... § 36.4318 Servicer tier ranking—temporary procedures. (a) The Secretary shall assign to each servicer a “Tier Ranking” based upon the servicer's performance in servicing guaranteed loans. There shall be four...

Operational experience with CMS Tier-2 sites

International Nuclear Information System (INIS)

Gonzalez Caballero, I

2010-01-01

In the CMS computing model, more than one third of the computing resources are located at Tier-2 sites, which are distributed across the countries in the collaboration. These sites are the primary platform for user analyses; they host datasets that are created at Tier-1 sites, and users from all CMS institutes submit analysis jobs that run on those data through grid interfaces. They are also the primary resource for the production of large simulation samples for general use in the experiment. As a result, Tier-2 sites have an interesting mix of organized experiment-controlled activities and chaotic user-controlled activities. CMS currently operates about 40 Tier-2 sites in 22 countries, making the sites a far-flung computational and social network. We describe our operational experience with the sites, touching on our achievements, the lessons learned, and the challenges for the future.

PENERAPAN ARSITEKTUR MULTI-TIER DENGAN DCOM DALAM SUATU SISTEM INFORMASI

Directory of Open Access Journals (Sweden)

Kartika Gunadi

2001-01-01

Full Text Available Information System implementation using two-tier architecture result lack in several critical issues : reuse component, scalability, maintenance, and data security. The multi-tiered client/server architecture provides a good resolution to solve these problems that using DCOM technology . The software is made by using Delphi 4 Client/Server Suite and Microsoft SQL Server V. 7.0 as a database server software. The multi-tiered application is partitioned into thirds. The first is client application which provides presentation services. The second is server application which provides application services, and the third is database server which provides database services. This multi-tiered application software can be made in two model. They are Client/Server Windows model and Client/Server Web model with ActiveX Form Technology. In this research is found that making multi-tiered architecture with using DCOM technology can provide many benefits such as, centralized application logic in middle-tier, make thin client application, distributed load of data process in several machines, increases security with the ability in hiding data, dan fast maintenance without installing database drivers in every client. Abstract in Bahasa Indonesia : Penerapan sistem informasi menggunakan two-tier architecture mempunyai banyak kelemahan : penggunaan kembali komponen, skalabilitas, perawatan, dan keamanan data. Multi-tier Client-Server architecture mempunyai kemampuan untuk memecahkan masalah ini dengan DCOM teknologi. Perangkat lunak ini dapat dibuat menggunakan Delphi 4 Client/Server Suite dan Microsoft SQL Server 7.0 sebagai perangkat lunak database. Aplikasi program multi-tier ini dibagi menjadi tiga partisi. Pertama adalah aplikasi client menyediakan presentasi servis, kedua aplikasi server menyediakan servis aplikasi, dan ketiga aplikasi database menyediakan database servis. Perangkat lunak aplikasi multi-tier ini dapat dibuat dalam dua model, yaitu client

Unified storage systems for distributed Tier-2 centres

International Nuclear Information System (INIS)

Cowan, G A; Stewart, G A; Elwell, A

2008-01-01

The start of data taking at the Large Hadron Collider will herald a new era in data volumes and distributed processing in particle physics. Data volumes of hundreds of Terabytes will be shipped to Tier-2 centres for analysis by the LHC experiments using the Worldwide LHC Computing Grid (WLCG). In many countries Tier-2 centres are distributed between a number of institutes, e.g., the geographically spread Tier-2s of GridPP in the UK. This presents a number of challenges for experiments to utilise these centres efficaciously, as CPU and storage resources may be subdivided and exposed in smaller units than the experiment would ideally want to work with. In addition, unhelpful mismatches between storage and CPU at the individual centres may be seen, which make efficient exploitation of a Tier-2's resources difficult. One method of addressing this is to unify the storage across a distributed Tier-2, presenting the centres' aggregated storage as a single system. This greatly simplifies data management for the VO, which then can access a greater amount of data across the Tier-2. However, such an approach will lead to scenarios where analysis jobs on one site's batch system must access data hosted on another site. We investigate this situation using the Glasgow and Edinburgh clusters, which are part of the ScotGrid distributed Tier-2. In particular we look at how to mitigate the problems associated with 'distant' data access and discuss the security implications of having LAN access protocols traverse the WAN between centres

76 FR 18259 - Announcement Regarding Delaware Triggering “on” Tier Four of Emergency Unemployment Compensation...

Science.gov (United States)

2011-04-01

... Triggering ``on'' Tier Four of Emergency Unemployment Compensation 2008 (EUC08) AGENCY: Employment and...'' Tier Four of Emergency Unemployment Compensation 2008 (EUC08). Public Law 111-312 extended provisions... the EUC08 program for qualified unemployed workers claiming benefits in high unemployment states. The...

Design of multi-tiered database application based on CORBA component

International Nuclear Information System (INIS)

Sun Xiaoying; Dai Zhimin

2003-01-01

As computer technology quickly developing, middleware technology changed traditional two-tier database system. The multi-tiered database system, consisting of client application program, application servers and database serves, is mainly applying. While building multi-tiered database system using CORBA component has become the mainstream technique. In this paper, an example of DUV-FEL database system is presented, and then discuss the realization of multi-tiered database based on CORBA component. (authors)

Breaks Are Better: A Tier II Social Behavior Intervention

Science.gov (United States)

Boyd, R. Justin; Anderson, Cynthia M.

2013-01-01

Multi-tiered systems of social behavioral support in schools provide varying levels of intervention matched to student need. Tier I (primary or universal) systems are for all students and are designed to promote pro-social behavior. Tier III (tertiary or intensive) supports are for students who engage in serious challenging behavior that has not…

Potentialities of high temperature reactors (HTR)

International Nuclear Information System (INIS)

Hittner, D.

2001-01-01

This articles reviews the assets of high temperature reactors concerning the amount of radioactive wastes produced. 2 factors favors HTR-type reactors: high thermal efficiency and high burn-ups. The high thermal efficiency is due to the high temperature of the coolant, in the case of the GT-MHR project (a cooperation between General Atomic, Minatom, Framatome, and Fuji Electric) designed to burn Russian military plutonium, the expected yield will be 47% with an outlet helium temperature of 850 Celsius degrees. The high temperature of the coolant favors a lot of uses of the heat generated by the reactor: urban heating, chemical processes, or desalination of sea water.The use of a HTR-type reactor in a co-generating way can value up to 90% of the energy produced. The high burn-up is due to the technology of HTR-type fuel that is based on encapsulation of fuel balls with heat-resisting materials. The nuclear fuel of Fort-Saint-Vrain unit (Usa) has reached values of burn-ups from 100.000 to 120.000 MWj/t. It is shown that the quantity of unloaded spent fuel can be divided by 4 for the same amount of electricity produced, in the case of the GT-MHR project in comparison with a light water reactor. (A.C.)

1990 Tier Two emergency and hazardous chemical inventory

International Nuclear Information System (INIS)

1991-03-01

This document contains the 1990 Two Tier Emergency and Hazardous Chemical Inventory. Submission of this Tier Two form (when requested) is required by Title 3 of the Superfund Amendments and Reauthorization Act of 1986, Section 312, Public Law 99--499, codified at 42 U.S.C. Section 11022. The purpose of this Tier Two form is to provide State and local officials and the public with specific information on hazardous chemicals present at your facility during the past year

Testing of research reactor fuel in the high flux reactor (Petten)

International Nuclear Information System (INIS)

Guidez, J.; Markgraf, J.W.; Sordon, G.; Wijtsma, F.J.; Thijssen, P.J.M.; Hendriks, J.A.

1999-01-01

The two types of fuel most frequently used by the main research reactors are metallic: highly enriched uranium (>90%) and silicide low enriched uranium ( 3 . However, a need exists for research on new reactor fuel. This would permit some plants to convert without losses in flux or in cycle length and would allow new reactor projects to achieve higher possibilities especially in fluxes. In these cases research is made either on silicide with higher density, or on other types of fuel (UMo, etc.). In all cases when new fuel is proposed, there is a need, for safety reasons, to test it, especially regarding the mechanical evolution due to burn-up (swelling, etc.). Initially, such tests are often made with separate plates, but lately, using entire elements. Destructive examinations are often necessary. For this type of test, the High Flux Reactor, located in Petten (The Netherlands) has many specific advantages: a large core, providing a variety of interesting positions with high fluence rate; a downward coolant flow simplifies the engineering of the device; there exists easy access with all handling possibilities to the hot-cells; the high number of operating days (>280 days/year), together with the high flux, gives a possibility to reach quickly the high burn-up needs; an experienced engineering department capable of translating specific requirements to tailor-made experimental devices; a well equipped hot-cell laboratory on site to perform all necessary measurements (swelling, γ-scanning, profilometry) and all destructive examinations. In conclusion, the HFR reactor readily permits experimental research on specific fuels used for research reactors with all the necessary facilities on the Petten site. (author)

High-temperature and breeder reactors - economic nuclear reactors of the future

International Nuclear Information System (INIS)

Djalilzadeh, A.M.

1977-01-01

The thesis begins with a review of the theory of nuclear fission and sections on the basic technology of nuclear reactors and the development of the first generation of gas-cooled reactors applied to electricity generation. It then deals in some detail with currently available and suggested types of high temperature reactor and with some related subsidiary issues such as the coupling of different reactor systems and various schemes for combining nuclear reactors with chemical processes (hydrogenation, hydrogen production, etc.), going on to discuss breeder reactors and their application. Further sections deal with questions of cost, comparison of nuclear with coal- and oil-fired stations, system analysis of reactor systems and the effect of nuclear generation on electricity supply. (C.J.O.G.)

The ATLAS Tier-0 Overview and operational experience

CERN Document Server

Elsing, M; Nairz, A; Negri, G

2010-01-01

Within the ATLAS hierarchical, multi-tier computing infrastructure, the Tier-0 centre at CERN is mainly responsible for prompt processing of the raw data coming from the online DAQ system, to archive the raw and derived data on tape, to register the data with the relevant catalogues and to distribute them to the associated Tier-1 centers. The Tier-0 is already fully functional. It has been successfully participating in all cosmic and commissioning data taking since May 2007, and was ramped up to its foreseen full size, performance and throughput for the cosmic (and short single-beam) run periods between July and October 2008. Data and work flows for collision data taking were exercised in several "Full Dress Rehearsals" (FDRs) in the course of 2008. The transition from an expert to a shifter-based system was successfully established in July 2008. This article will give an overview of the Tier-0 system, its data and work flows, and operations model. It will review the operational experience gained in cosmic, c...

47 CFR 76.1605 - New product tier.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false New product tier. 76.1605 Section 76.1605 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Notices § 76.1605 New product tier. (a) Within 30 days of the offering of an...

26 CFR 1.444-4 - Tiered structure.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 6 2010-04-01 2010-04-01 false Tiered structure. 1.444-4 Section 1.444-4 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Accounting Periods § 1.444-4 Tiered structure. (a) Electing small business trusts. For...

Home/community-based services: a two-tier approach.

Science.gov (United States)

Aponte, H J; Zarski, J J; Bixenstine, C; Cibik, P

1991-07-01

A two-tier model for work with high-risk families is presented. It combines multiple-family groups in the community with home-based family therapy for individual families. The ecostructural conceptual framework of the model is discussed, and its application is illustrated by a case vignette.

Assessment of the Capability of Molten Salt Reactors as a Next Generation High Temperature Reactors

International Nuclear Information System (INIS)

Elsheikh, B.M.

2017-01-01

Molten Salt Reactor according to Aircraft Reactor Experiment (ARE) and the Molten Salt Reactor Experiment (MSRE) programs, was designed to be the first full-scale, commercial nuclear power plant utilizing molten salt liquid fuels that can be used for producing electricity, and producing fissile fuels (breeding)burning actinides. The high temperature in the primary cycle enables the realization of efficient thermal conversion cycles with net thermal efficiencies reach in some of the designs of nuclear reactors greater than 45%. Molten salts and liquid salt because of their low vapor pressure are excellent candidates for meeting most of the requirements of these high temperature reactors. There is renewed interest in MSRs because of changing goals and new technologies in the use of high-temperature reactors. Molten Salt Reactors for high temperature create substantial technical challenges to have high effectiveness intermediate heat transfer loop components. This paper will discuss and investigate the capability and compatibility of molten salt reactors, toward next generation high temperature energy system and its technical challenges

Tiers of intervention in kindergarten through third grade.

Science.gov (United States)

O'Connor, Rollanda E; Harty, Kristin R; Fulmer, Deborah

2005-01-01

This study measured the effects of increasing levels of intervention in reading for a cohort of children in Grades K through 3 to determine whether the severity of reading disability (RD) could be significantly reduced in the catchment schools. Tier 1 consisted of professional development for teachers of reading. The focus of this study is on additional instruction that was provided as early as kindergarten for children whose achievement fell below average. Tier 2 intervention consisted of small-group reading instruction 3 times per week, and Tier 3 of daily instruction delivered individually or in groups of two. A comparison of the reading achievement of third-grade children who were at risk in kindergarten showed moderate to large differences favoring children in the tiered interventions in decoding, word identification, fluency, and reading comprehension.

75 FR 73166 - Publication of the Tier 2 Tax Rates

Science.gov (United States)

2010-11-29

... DEPARTMENT OF THE TREASURY Internal Revenue Service Publication of the Tier 2 Tax Rates AGENCY: Internal Revenue Service, Treasury. ACTION: Notice. SUMMARY: Publication of the tier 2 tax rates for...). Tier 2 taxes on railroad employees, employers, and employee representatives are one source of funding...

76 FR 71623 - Publication of the Tier 2 Tax Rates

Science.gov (United States)

2011-11-18

... DEPARTMENT OF THE TREASURY Internal Revenue Service Publication of the Tier 2 Tax Rates AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice. SUMMARY: Publication of the tier 2 tax rates for...). Tier 2 taxes on railroad employees, employers, and employee representatives are one source of funding...

78 FR 71039 - Publication of the Tier 2 Tax Rates

Science.gov (United States)

2013-11-27

... DEPARTMENT OF THE TREASURY Internal Revenue Service Publication of the Tier 2 Tax Rates AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice. SUMMARY: Publication of the tier 2 tax rates for...). Tier 2 taxes on railroad employees, employers, and employee representatives are one source of funding...

Prevalence of syphilis infection in different tiers of female sex workers in China: implications for surveillance and interventions

Directory of Open Access Journals (Sweden)

Chen Xiang-Sheng

2012-04-01

Full Text Available Abstract Background Syphilis has made a dramatic resurgence in China during the past two decades and become the third most prevalent notifiable infectious disease in China. Female sex workers (FSWs have become one of key populations for the epidemic. In order to investigate syphilis infection among different tiers of FSWs, a cross-sectional study was conducted in 8 sites in China. Methods Serum specimens (n = 7,118 were collected to test for syphilis and questionnaire interviews were conducted to obtain socio-demographic and behavioral information among FSWs recruited from different types of venues. FSWs were categorized into three tiers (high-, middle- and low-tier FSWs based on the venues where they solicited clients. Serum specimens were screened with enzyme-linked immunosorbent assay (ELISA for treponemal antibody followed by confirmation with non-treponemal toluidine red unheated serum test (TRUST for positive ELISA specimens to determine syphilis infection. A logistic regression model was used to determine factors associated with syphilis infection. Results Overall syphilis prevalence was 5.0% (95%CI, 4.5-5.5%. Low-tier FSWs had the highest prevalence (9.7%; 95%CI, 8.3-11.1%, followed by middle-tier (4.3%; 95%CI, 3.6-5.0%, P P Conclusions This multi-site survey showed a high prevalence of syphilis infection among FSWs and substantial disparities in syphilis prevalence by the tier of FSWs. The difference in syphilis prevalence is substantial between different tiers of FSWs, with the highest rate among low-tier FSWs. Thus, current surveillance and intervention activities, which have low coverage in low-tier FSWs in China, should be further examined.

Design requirements of instrumentation and control systems for next generation reactor

International Nuclear Information System (INIS)

Koo, In Soo; Lee, Byung Sun; Park, Kwang Hyun; Park, Heu Yoon; Lee, Dong Young; Kim, Jung Taek; Hwang, In Koo; Chung, Chul Hwan; Hur, Seop; Kim, Chang Hoi; Na, Nan Ju

1994-03-01

In this report, the basic design requirements of Instrumentation and Control systems for next generation reactor are described, which are top-tier level, to support the advanced I and C systems. It contains the requirements in accordance with the plant reliability, the plant performance, the operator's aid functions, the features for maintenance and testing, licensing issues for I and C systems. Advanced I and C systems are characterized such as the application of the digital and the human engineering technologies. To development of this requirements, the I and C systems for the foreign passive and the evolutionary types of reactor and the domestic conventional reators were reviewed and anlysed. At the detail design stage, these requirements will be used for top-tier requirements. To develop the detail design requirements in the future, more quantitive and qualitive analyses are need to be added. (Author) 44 refs

Design requirements of instrumentation and control systems for next generation reactor

Energy Technology Data Exchange (ETDEWEB)

Koo, In Soo; Lee, Byung Sun; Park, Kwang Hyun; Park, Heu Yoon; Lee, Dong Young; Kim, Jung Taek; Hwang, In Koo; Chung, Chul Hwan; Hur, Seop; Kim, Chang Hoi; Na, Nan Ju [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1994-03-01

In this report, the basic design requirements of Instrumentation and Control systems for next generation reactor are described, which are top-tier level, to support the advanced I and C systems. It contains the requirements in accordance with the plant reliability, the plant performance, the operator`s aid functions, the features for maintenance and testing, licensing issues for I and C systems. Advanced I and C systems are characterized such as the application of the digital and the human engineering technologies. To development of this requirements, the I and C systems for the foreign passive and the evolutionary types of reactor and the domestic conventional reators were reviewed and anlysed. At the detail design stage, these requirements will be used for top-tier requirements. To develop the detail design requirements in the future, more quantitive and qualitive analyses are need to be added. (Author) 44 refs.

Modular high-temperature gas-cooled reactor

International Nuclear Information System (INIS)

Shepherd, L.R.

1988-01-01

The high financial risk involved in building large nuclear power reactors has been a major factor in halting investment in new plant and in bringing further technical development to a standstill. Increased public concern about the safety of nuclear plant, particularly after Chernobyl, has contributed to this stagnation. Financial and technical risk could be reduced considerably by going to small modular units, which would make it possible to build up power station capacity in small steps. Such modular plant, based on the helium-cooled high temperature reactor (HTR), offers remarkable advantages in terms of inherent safety characteristics, partly because of the relatively small size of the individual modules but more on account of the enormous thermal capacity and high temperature margins of the graphitic reactor assemblies. Assessments indicate that, in the USA, the cost of power from the modular systems would be less than that from conventional single reactor plant, up to about 600 MW(e), and only marginally greater above that level, a margin that should be offset by the shorter time required in bringing the modular units on line to earn revenue. The modular HTR would be particularly appropriate in the UK, because of the considerable British industrial background in gas-cooled reactors, and could be a suitable replacement for Magnox. The modular reactor would be particularly suited to combined heat and power schemes and would offer great potential for the eventual development of gas turbine power conversion and the production of high-temperature process heat. (author)

ATLAS Tier-2 monitoring system for the German cloud

Energy Technology Data Exchange (ETDEWEB)

Meyer, Joerg; Quadt, Arnulf; Weber, Pavel [II. Physikalisches Institut, Georg-August-Universitaet, Goettingen (Germany)

2011-07-01

The ATLAS tier centers in Germany provide their computing resources for the ATLAS experiment. The stable and sustainable operation of this so-called DE-cloud heavily relies on effective monitoring of the Tier-1 center GridKa and its associated Tier-2 centers. Central and local grid information services constantly collect and publish the status information from many computing resources and sites. The cloud monitoring system discussed in this presentation evaluates the information related to different cloud resources and provides a coherent and comprehensive view of the cloud. The main monitoring areas covered by the tool are data transfers, cloud software installation, site batch systems, Service Availability Monitoring (SAM). The cloud monitoring system consists of an Apache-based Python application, which retrieves the information and publishes it on the generated HTML web page. This results in an easy-to-use web interface for the limited number of sites in the cloud with fast and efficient access to the required information starting from a high level summary for the whole cloud to detailed diagnostics for the single site services. This approach provides the efficient identification of correlated site problems and simplifies the administration on both cloud and site level.

The ATLAS Tier-0: Overview and operational experience

International Nuclear Information System (INIS)

Elsing, Markus; Goossens, Luc; Nairz, Armin; Negri, Guido

2010-01-01

Within the ATLAS hierarchical, multi-tier computing infrastructure, the Tier-0 centre at CERN is mainly responsible for prompt processing of the raw data coming from the online DAQ system, to archive the raw and derived data on tape, to register the data with the relevant catalogues and to distribute them to the associated Tier-1 centers. The Tier-0 is already fully functional. It has been successfully participating in all cosmic and commissioning data taking since May 2007, and was ramped up to its foreseen full size, performance and throughput for the cosmic (and short single-beam) run periods between July and October 2008. Data and work flows for collision data taking were exercised in several 'Full Dress Rehearsals' (FDRs) in the course of 2008. The transition from an expert to a shifter-based system was successfully established in July 2008. This article will give an overview of the Tier-0 system, its data and work flows, and operations model. It will review the operational experience gained in cosmic, commissioning, and FDR exercises during the past year. And it will give an outlook on planned developments and the evolution of the system towards first collision data taking expected now in late Autumn 2009.

The ATLAS Tier-0: Overview and operational experience

Science.gov (United States)

Elsing, Markus; Goossens, Luc; Nairz, Armin; Negri, Guido

2010-04-01

Within the ATLAS hierarchical, multi-tier computing infrastructure, the Tier-0 centre at CERN is mainly responsible for prompt processing of the raw data coming from the online DAQ system, to archive the raw and derived data on tape, to register the data with the relevant catalogues and to distribute them to the associated Tier-1 centers. The Tier-0 is already fully functional. It has been successfully participating in all cosmic and commissioning data taking since May 2007, and was ramped up to its foreseen full size, performance and throughput for the cosmic (and short single-beam) run periods between July and October 2008. Data and work flows for collision data taking were exercised in several "Full Dress Rehearsals" (FDRs) in the course of 2008. The transition from an expert to a shifter-based system was successfully established in July 2008. This article will give an overview of the Tier-0 system, its data and work flows, and operations model. It will review the operational experience gained in cosmic, commissioning, and FDR exercises during the past year. And it will give an outlook on planned developments and the evolution of the system towards first collision data taking expected now in late Autumn 2009.

High temperature reactor safety and environment

International Nuclear Information System (INIS)

Brisbois, J.; Charles, J.

1975-01-01

High-temperature reactors are endowed with favorable safety and environmental factors resulting from inherent design, main-component safety margins, and conventional safety systems. The combination of such characteristics, along with high yields, prove in addition, that such reactors are plagued with few problems, can be installed near users, and broaden the recourse to specific power, therefore fitting well within a natural environment [fr

Acute tier-1 and tier-2 effect assessment approaches in the EFSA Aquatic Guidance Diocument: are they sufficiently protective for insecticides?

NARCIS (Netherlands)

Wijngaarden, van R.P.A.; Maltby, L.; Brock, T.C.M.

2015-01-01

BACKGROUND The objective of this paper is to evaluate whether the acute tier-1 and tier-2 methods as proposed by the Aquatic Guidance Document recently published by the European Food Safety Authority (EFSA) are appropriate for deriving regulatory acceptable concentrations (RACs) for insecticides.

Studies Related to the Oregon State University High Temperature Test Facility: Scaling, the Validation Matrix, and Similarities to the Modular High Temperature Gas-Cooled Reactor

Energy Technology Data Exchange (ETDEWEB)

Richard R. Schultz; Paul D. Bayless; Richard W. Johnson; William T. Taitano; James R. Wolf; Glenn E. McCreery

2010-09-01

The Oregon State University (OSU) High Temperature Test Facility (HTTF) is an integral experimental facility that will be constructed on the OSU campus in Corvallis, Oregon. The HTTF project was initiated, by the U.S. Nuclear Regulatory Commission (NRC), on September 5, 2008 as Task 4 of the 5 year High Temperature Gas Reactor Cooperative Agreement via NRC Contract 04-08-138. Until August, 2010, when a DOE contract was initiated to fund additional capabilities for the HTTF project, all of the funding support for the HTTF was provided by the NRC via their cooperative agreement. The U.S. Department of Energy (DOE) began their involvement with the HTTF project in late 2009 via the Next Generation Nuclear Plant project. Because the NRC interests in HTTF experiments were only centered on the depressurized conduction cooldown (DCC) scenario, NGNP involvement focused on expanding the experimental envelope of the HTTF to include steady-state operations and also the pressurized conduction cooldown (PCC). Since DOE has incorporated the HTTF as an ingredient in the NGNP thermal-fluids validation program, several important outcomes should be noted: 1. The reference prismatic reactor design, that serves as the basis for scaling the HTTF, became the modular high temperature gas-cooled reactor (MHTGR). The MHTGR has also been chosen as the reference design for all of the other NGNP thermal-fluid experiments. 2. The NGNP validation matrix is being planned using the same scaling strategy that has been implemented to design the HTTF, i.e., the hierarchical two-tiered scaling methodology developed by Zuber in 1991. Using this approach a preliminary validation matrix has been designed that integrates the HTTF experiments with the other experiments planned for the NGNP thermal-fluids verification and validation project. 3. Initial analyses showed that the inherent power capability of the OSU infrastructure, which only allowed a total operational facility power capability of 0.6 MW, is

Multiple tier fuel cycle studies for waste transmutation

International Nuclear Information System (INIS)

Hill, R.N.; Taiwo, T.A.; Stillman, J.A.; Graziano, D.J.; Bennett, D.R.; Trellue, H.; Todosow, M.; Halsey, W.G.; Baxter, A.

2002-01-01

As part of the U.S. Department of Energy Advanced Accelerator Applications Program, a systems study was conducted to evaluate the transmutation performance of advanced fuel cycle strategies. Three primary fuel cycle strategies were evaluated: dual-tier systems with plutonium separation, dual-tier systems without plutonium separation, and single-tier systems without plutonium separation. For each case, the system mass flow and TRU consumption were evaluated in detail. Furthermore, the loss of materials in fuel processing was tracked including the generation of new waste streams. Based on these results, the system performance was evaluated with respect to several key transmutation parameters including TRU inventory reduction, radiotoxicity, and support ratio. The importance of clean fuel processing (∼0.1% losses) and inclusion of a final tier fast spectrum system are demonstrated. With these two features, all scenarios capably reduce the TRU and plutonium waste content, significantly reducing the radiotoxicity; however, a significant infrastructure (at least 1/10 the total nuclear capacity) is required for the dedicated transmutation system

75 FR 69134 - Announcement Regarding States Triggering “off” of Tiers Three and Four of Emergency Unemployment...

Science.gov (United States)

2010-11-10

... Triggering ``off'' of Tiers Three and Four of Emergency Unemployment Compensation 2008 (EUC08) AGENCY... triggering ``off'' of Tiers Three and Four of the Emergency Unemployment Compensation (EUC08) program. Public... high unemployment states. The Department of Labor produces a trigger notice indicating which states...

76 FR 44611 - Announcement Regarding States Triggering “Off” of Tiers Three and Four of Emergency Unemployment...

Science.gov (United States)

2011-07-26

... Triggering ``Off'' of Tiers Three and Four of Emergency Unemployment Compensation 2008 (EUC08) AGENCY... triggering ``off'' of Tiers Three and Four of the Emergency Unemployment Compensation (EUC08) program. Public... high unemployment states. The Department of Labor produces a trigger notice indicating which states...

Very-high-temperature reactors for future use

International Nuclear Information System (INIS)

Kasten, P.R.

1988-08-01

Very-high-temperature reactors (VHTRs) show promise for economic generation of electricity and of high-temperature process heat. The key is the development of high-temperature materials which permit gas turbine VHTRs to generate electricity economically, at reactor coolant temperatures which can be used for fossil fuel conversion processes. 7 refs., 5 figs

Tier2 Submit Software

Science.gov (United States)

Download this tool for Windows or Mac, which helps facilities prepare a Tier II electronic chemical inventory report. The data can also be exported into the CAMEOfm (Computer-Aided Management of Emergency Operations) emergency planning software.

The microbial community of a biofilm contact reactor for the treatment of winery wastewater.

Science.gov (United States)

de Beer, D M; Botes, M; Cloete, T E

2018-02-01

To utilize a three-tiered approach to provide insight into the microbial community structure, the spatial distribution and the metabolic capabilities of organisms of a biofilm in the two towers of a high-rate biological contact reactor treating winery wastewater. Next-generation sequencing indicated that bacteria primarily responsible for the removal of carbohydrates, sugars and alcohol were more abundant in tower 1 than tower 2 while nitrifying and denitrifying bacteria were more abundant in tower 2. Yeast populations differed in each tower. Fluorescent in situ hybridization coupled with confocal microscopy showed distribution of organisms confirming an oxygen gradient across the biofilm depth. The Biolog system (ECO plates) specified the different carbon-metabolizing profiles of the two biofilms. The three-tiered approach confirmed that the addition of a second subunit to the bioreactor, expanded the treatment capacity by augmenting the microbial and metabolic diversity of the system, improving the treatment scope of the system. A three-tiered biofilm analysis provided data required to optimize the design of a bioreactor to provide favourable conditions for the development of a microbial consortium, which has optimal waste removal properties for the treatment requirements at hand. © 2017 The Society for Applied Microbiology.

A reactor for high-throughput high-pressure nuclear magnetic resonance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Beach, N. J.; Knapp, S. M. M.; Landis, C. R., E-mail: landis@chem.wisc.edu [Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53719 (United States)

2015-10-15

The design of a reactor for operando nuclear magnetic resonance (NMR) monitoring of high-pressure gas-liquid reactions is described. The Wisconsin High Pressure NMR Reactor (WiHP-NMRR) design comprises four modules: a sapphire NMR tube with titanium tube holder rated for pressures as high as 1000 psig (68 atm) and temperatures ranging from −90 to 90 °C, a gas circulation system that maintains equilibrium concentrations of dissolved gases during gas-consuming or gas-releasing reactions, a liquid injection apparatus that is capable of adding measured amounts of solutions to the reactor under high pressure conditions, and a rapid wash system that enables the reactor to be cleaned without removal from the NMR instrument. The WiHP-NMRR is compatible with commercial 10 mm NMR probes. Reactions performed in the WiHP-NMRR yield high quality, information-rich, and multinuclear NMR data over the entire reaction time course with rapid experimental turnaround.

Which Tier? Effects of Linear Assessment and Student Characteristics on GCSE Entry Decisions

Science.gov (United States)

Vitello, Sylvia; Crawford, Cara

2018-01-01

In England, students obtain General Certificate of Secondary Education (GCSE) qualifications, typically at age 16. Certain GCSEs are tiered; students take either higher-level (higher tier) or lower-level (foundation tier) exams, which may have different educational, career and psychological consequences. In particular, foundation tier entry, if…

Performance analysis of a handoff scheme for two-tier cellular CDMA networks

Directory of Open Access Journals (Sweden)

Ahmed Hamad

2011-07-01

Full Text Available A two-tier model is used in cellular networks to improve the Quality of Service (QoS, namely to reduce the blocking probability of new calls and the forced termination probability of ongoing calls. One tier, the microcells, is used for slow or stationary users, and the other, the macrocell, is used for high speed users. In Code-Division Multiple-Access (CDMA cellular systems, soft handoffs are supported, which provides ways for further QoS improvement. In this paper, we introduce such a way; namely, a channel borrowing scheme used in conjunction with a First-In-First-Out (FIFO queue in the macrocell tier. A multidimensional Markov chain to model the resulting system is established, and an iterative technique to find the steady-state probability distribution is utilized. This distribution is then used to find the performance measures of interest: new call blocking probability, and forced termination probability.

Multiple Tier Fuel Cycle Studies for Waste Transmutation

International Nuclear Information System (INIS)

Hill, R.N.; Taiwo, T.A.; Stillman, J.A.; Graziano, D.J.; Bennett, D.R.; Trellue, H.; Todosow, M.; Halsey, W.G.; Baxter, A.

2002-01-01

As part of the U.S. Department of Energy Advanced Accelerator Applications Program, a systems study was conducted to evaluate the transmutation performance of advanced fuel cycle strategies. Three primary fuel cycle strategies were evaluated: dual-tier systems with plutonium separation, dual-tier systems without plutonium separation, and single-tier systems without plutonium separation. For each case, the system mass flow and TRU consumption were evaluated in detail. Furthermore, the loss of materials in fuel processing was tracked including the generation of new waste streams. Based on these results, the system performance was evaluated with respect to several key transmutation parameters including TRU inventory reduction, radiotoxicity, and support ratio. The importance of clean fuel processing (∼0.1% losses) and inclusion of a final tier fast spectrum system are demonstrated. With these two features, all scenarios capably reduce the TRU and plutonium waste content, significantly reducing the radiotoxicity; however, a significant infrastructure (at least 1/10 the total nuclear capacity) is required for the dedicated transmutation system. (authors)

High temperature gas cooled nuclear reactor

International Nuclear Information System (INIS)

Hosegood, S.B.; Lockett, G.E.

1975-01-01

For high-temperature gas cooled reactors it is considered advantageous to design the core so that the moderator blocks can be removed and replaced by some means of standpipes normally situated in the top of the reactor vessel. An arrangement is here described to facilitate these operations. The blocks have end faces shaped as irregular hexagons with three long sides of equal length and three short sides also of equal length, one short side being located between each pair of adjacent long sides, and the long sides being inclined towards one another at 60 0 . The block defines a number of coolant channels located parallel to its sides. Application of the arrangement to a high temperature gas-cooled reactor with refuelling standpipes is described. The standpipes are located in the top of the reactor vessel above the tops of the columns and are disposed coaxially above the hexagonal channels, with diameters that allow the passage of the blocks. (U.K.)

Leaders Growing Leaders: Designing a Tier-Based Leadership Program for Surgeons.

Science.gov (United States)

Torbeck, Laura; Rozycki, Grace; Dunnington, Gary

2018-02-07

Leadership has emerged as a crucial component of professional development for physicians in academic medicine. Most leadership skills can be learned and therefore best practices of delivering leadership development are in high demand. For practicing surgeons, specific strategies to teach leadership have been lacking. The purpose of this paper is to describe the structure of a tier-based leadership development program called Leaders Growing Leaders, to identify the major curricular components to each tier including measures and outcomes, and to share lessons learned for those who may want to begin a similar leadership development program. Copyright © 2018 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Tenet: An Architecture for Tiered Embedded Networks

OpenAIRE

Ramesh Govindan; Eddie Kohler; Deborah Estrin; Fang Bian; Krishna Chintalapudi; Om Gnawali; Sumit Rangwala; Ramakrishna Gummadi; Thanos Stathopoulos

2005-01-01

Future large-scale sensor network deployments will be tiered, with the motes providing dense sensing and a higher tier of 32-bit master nodes with more powerful radios providing increased overall network capacity. In this paper, we describe a functional architecture for wireless sensor networks that leverages this structure to simplify the overall system. Our Tenet architecture has the nice property that the mote-layer software is generic and reusable, and all application functionality reside...

Thermal Energetic Reactor with High Reproduction of Fission Materials

International Nuclear Information System (INIS)

Kotov, V.M.

2012-01-01

Existing thermal reactors are energy production scale limited because of low portion of raw uranium usage. Fast reactors are limited by reprocessing need of huge mass of raw uranium at the initial stage of development. The possibility of development of thermal reactors with high fission materials reproduction, which solves the problem, is discussed here. Neutron losses are decreased, uranium-thorium fuel with artificial fission materials equilibrium regime is used, additional in-core and out-core neutron sources are used for supplying of high fission materials reproduction. Liquid salt reactors can use dynamic loading regime for this purpose. Preferable construction is channel type reactor with heavy water moderator. Good materials for fuel element shells and channel walls are zirconium alloys enriched by 90Zr. Water cooled reactors with usage 12% of raw uranium and liquid metal cooled reactors with usage 25% of raw uranium are discussed. Reactors with additional neutron sources obtain full usage of raw uranium with small additional energy expenses. On the base of thermal reactors with high fission materials reproduction world atomic power engineering development supplying higher power and requiring smaller speed of raw uranium mining, than in the variant with fast reactors, is possible.

The architecture and operation of the CMS Tier-0

International Nuclear Information System (INIS)

Hufnagel, Dirk

2011-01-01

The Tier-0 processing system is the initial stage of the multi-tiered computing system of CMS. It takes care of the first processing steps of data at the LHC at CERN. The automated workflows running in the Tier-0 contain both low-latency processing chains for time-critical applications and bulk chains to archive the recorded data offsite the host laboratory. It is a mix between an online and offline system, because the data the CMS DAQ writes out initially is of a temporary nature. Most of the complexity in the design of this system comes from this unique combination of online and offline use cases and dependencies. In this talk, we want to present the software design of the CMS Tier-0 system and present an analysis of the 24/7 operation of the system in the 2009/2010 data taking periods.

25 CFR 542.20 - What is a Tier A gaming operation?

Science.gov (United States)

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false What is a Tier A gaming operation? 542.20 Section 542.20 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR HUMAN SERVICES MINIMUM INTERNAL CONTROL STANDARDS § 542.20 What is a Tier A gaming operation? A Tier A gaming operation is one with annual...

25 CFR 542.30 - What is a Tier B gaming operation?

Science.gov (United States)

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false What is a Tier B gaming operation? 542.30 Section 542.30 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR HUMAN SERVICES MINIMUM INTERNAL CONTROL STANDARDS § 542.30 What is a Tier B gaming operation? A Tier B gaming operation is one with gross...

25 CFR 542.40 - What is a Tier C gaming operation?

Science.gov (United States)

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false What is a Tier C gaming operation? 542.40 Section 542.40 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR HUMAN SERVICES MINIMUM INTERNAL CONTROL STANDARDS § 542.40 What is a Tier C gaming operation? A Tier C gaming operation is one with annual...

Illustrative Example of Distributed Analysis in ATLAS Spanish Tier-2 and Tier-3 centers

CERN Document Server

Oliver, E; The ATLAS collaboration; González de la Hoz, S; Kaci, M; Lamas, A; Salt, J; Sánchez, J; Villaplana, M

2011-01-01

Data taking in ATLAS has been going on for more than one year. The necessity of a computing infrastructure for data storage, access for thousands of users and process of hundreds of million of events has been confirmed in this period. Fortunately, this task has been managed by the GRID infrastructure and the manpower that also has been developing specific GRID tools for the ATLAS community. An example of a physics analysis, searches for the decay of a heavy resonance into a ttbar pair, using this infrastructure is shown. Concretely using the ATLAS Spanish Tier-2 and the IFIC Tier-3. In this moment, the ATLAS Distributed Computing group is working to improve the connectivity among centers in order to be ready for the foreseen increase on the ATLAS activity in the next years.

High-temperature reactor in modular construction

International Nuclear Information System (INIS)

Mueller, F.U.; Reutler, H.; Ullrich, M.

1981-01-01

Together with other reactors of the same type a gas-cooled, small-sized high-temperature reactor is to be assembled into a plant with modular design. The reactor vessel can be withdrawn as a whole after shutdown, removal of the fuel element charge, disassembly of the control rods, and opening of the closure of the safety containment. All apertures for the inlet and outlet of the cooling gas are located in the ground plate of the reactor. The lower part of the reactor cavern serves as inlet space for the cool gas, while the heated gas is let in through a line of a heat sink, e.g. a heat exchanger. The ground plate is connected with the hot gas line or with an inserted hot gas collecting room by means of a simple plug connection which is released automatically when the reactor vessel is withdrawn. The cooling gas, which is put into circulation by a blower and led through special conducting systems, is also used for cooling the outer metal jacket of the hot gas line. A second design is described according to which the reactor and heat exchanger are superposed in a safety containment, such as applied for pressurized water-cooled nuclear reactors. (orig.) [de

Nuclear reactor application for high temperature power industrial processes

International Nuclear Information System (INIS)

Dollezhal', N.A.; Zaicho, N.D.; Alexeev, A.M.; Baturov, B.B.; Karyakin, Yu.I.; Nazarov, E.K.; Ponomarev-Stepnoj, N.N.; Protzenko, A.M.; Chernyaev, V.A.

1977-01-01

This report gives the results of considerations on industrial heat and technology processes (in chemistry, steelmaking, etc.) from the point of view of possible ways, technical conditions and nuclear safety requirements for the use of high temperature reactors in these processes. Possible variants of energy-technological diagrams of nuclear-steelmaking, methane steam-reforming reaction and other processes, taking into account the specific character of nuclear fuel are also given. Technical possibilities and economic conditions of the usage of different types of high temperature reactors (gas cooled reactors and reactors which have other means of transport of nuclear heat) in heat processes are examined. The report has an analysis of the problem, that arises with the application of nuclear reactors in energy-technological plants and an evaluation of solutions of this problem. There is a reason to suppose that we will benefit from the use of high temperature reactors in comparison with the production based on high quality fossil fuel [ru

Modular high-temperature reactor launched (and wallchart)

International Nuclear Information System (INIS)

Steinwarz, W.

1987-01-01

In view of the need for a technically unsophisticated, safe and economic reactor system, the KWU group has integrated the experience gained from German light-water reactor engineering and from successful operation of the German AVR experimental high-temperature reactor into the development of the High-Temperature Reactor (HTR)-module. The main components are illustrated and explained and technical data for the HTR-module is given. Safety is also considered. This includes graphs of core heat-up temperature for pebble-bed HTR and a graph of the temperature load of the fuel elements. The operation, control and applications are considered. The latter includes use in combined heat and power generation and community heating. Feasibility studies have shown that the HTR-module is cheaper, comparatively, than coal-fired power stations. (U.K.)

Tier 3 batch system data locality via managed caches

Science.gov (United States)

Fischer, Max; Giffels, Manuel; Jung, Christopher; Kühn, Eileen; Quast, Günter

2015-05-01

Modern data processing increasingly relies on data locality for performance and scalability, whereas the common HEP approaches aim for uniform resource pools with minimal locality, recently even across site boundaries. To combine advantages of both, the High- Performance Data Analysis (HPDA) Tier 3 concept opportunistically establishes data locality via coordinated caches. In accordance with HEP Tier 3 activities, the design incorporates two major assumptions: First, only a fraction of data is accessed regularly and thus the deciding factor for overall throughput. Second, data access may fallback to non-local, making permanent local data availability an inefficient resource usage strategy. Based on this, the HPDA design generically extends available storage hierarchies into the batch system. Using the batch system itself for scheduling file locality, an array of independent caches on the worker nodes is dynamically populated with high-profile data. Cache state information is exposed to the batch system both for managing caches and scheduling jobs. As a result, users directly work with a regular, adequately sized storage system. However, their automated batch processes are presented with local replications of data whenever possible.

Proceedings of the technical committee on high conversion and high burnup reactors

International Nuclear Information System (INIS)

Shiroya, Seiji; Kanda, Keiji; Sekiya, Tamotsu

1990-02-01

The present issue is the proceedings of 'the Technical Committee on High Conversion and High Burnup Reactors' held at Kyoto University Research Reactor Institute (KURRI) on December 12 and 22, 1988. In this committee, members so much concerned with this theme were asked to report their recent accomplishment and activities. By such a program, the committee was intended to make a survey of future direction of research in this type of reactor. (J.P.N.)

Tier II Chemical Storage Facilities

Data.gov (United States)

Iowa State University GIS Support and Research Facility — Facilities that store hazardous chemicals above certain quantities must submit an annual emergency and hazardous chemical inventory on a Tier II form. This is a...

Effects of a Tier 3 Self-Management Intervention Implemented with and without Treatment Integrity

Science.gov (United States)

Lower, Ashley; Young, K. Richard; Christensen, Lynnette; Caldarella, Paul; Williams, Leslie; Wills, Howard

2016-01-01

This study investigated the effects of a Tier 3 peer-matching self-management intervention on two elementary school students who had previously been less responsive to Tier 1 and Tier 2 interventions. The Tier 3 self-management intervention, which was implemented in the general education classrooms, included daily electronic communication between…

2-tiered antibody testing for early and late Lyme disease using only an immunoglobulin G blot with the addition of a VlsE band as the second-tier test.

Science.gov (United States)

Branda, John A; Aguero-Rosenfeld, Maria E; Ferraro, Mary Jane; Johnson, Barbara J B; Wormser, Gary P; Steere, Allen C

2010-01-01

Standard 2-tiered immunoglobulin G (IgG) testing has performed well in late Lyme disease (LD), but IgM testing early in the illness has been problematic. IgG VlsE antibody testing, by itself, improves early sensitivity, but may lower specificity. We studied whether elements of the 2 approaches could be combined to produce a second-tier IgG blot that performs well throughout the infection. Separate serum sets from LD patients and control subjects were tested independently at 2 medical centers using whole-cell enzyme immunoassays and IgM and IgG immunoblots, with recombinant VlsE added to the IgG blots. The results from both centers were combined, and a new second-tier IgG algorithm was developed. With standard 2-tiered IgM and IgG testing, 31% of patients with active erythema migrans (stage 1), 63% of those with acute neuroborreliosis or carditis (stage 2), and 100% of those with arthritis or late neurologic involvement (stage 3) had positive results. Using new IgG criteria, in which only the VlsE band was scored as a second-tier test among patients with early LD (stage 1 or 2) and 5 of 11 IgG bands were required in those with stage 3 LD, 34% of patients with stage 1, 96% of those with stage 2, and 100% of those with stage 3 infection had positive responses. Both new and standard testing achieved 100% specificity. Compared with standard IgM and IgG testing, the new IgG algorithm (with VlsE band) eliminates the need for IgM testing; it provides comparable or better sensitivity, and it maintains high specificity.

Gas cooled thermal reactors with high temperatures (VHTR)

International Nuclear Information System (INIS)

Bouchter, J.C.; Dufour, P.; Guidez, J.; Latge, C.; Renault, C.; Rimpault, G.; Vasile, A.

2014-01-01

VHTR is one of the 6 concepts retained for the 4. generation of nuclear reactors, it is an upgraded version of the HTR-type reactor (High Temperature Reactors). 5 HTR reactors were operated in the world in the eighties, now 2 experimental HTR are working in China and Japan and 2 HTR with an output power of 100 MWe are being built in China. The purpose of the VHTR is to provide an helium at very high temperatures around 1000 Celsius degrees that could be used directly in a thermochemical way to produce hydrogen for instance. HTR reactors are interesting in terms of safety but it does not optimise the consumption of uranium and the production of wastes. This article presents a brief historical account of HTR-type reactors and their main design and safety features. The possibility of using HTR to burn plutonium is also presented as well as the possibility of closing the fuel cycle and of using thorium-uranium fuel. (A.C.)

Digital control for nuclear reactors - lessons learned

International Nuclear Information System (INIS)

Bernard, J.A.; Aviles, B.N.; Lanning, D.D.

1992-01-01

Lessons learned during the course of the now decade-old MIT program on the digital control of nuclear reactors are enumerated. Relative to controller structure, these include the importance of a separate safety system, the need for signal validation, the role of supervisory algorithms, the significance of command validation, and the relevance of automated reasoning. Relative to controller implementation, these include the value of nodal methods to the creation of real-time reactor physics and thermal hydraulic models, the advantages to be gained from the use of real-time system models, and the importance of a multi-tiered structure to the simultaneous achievement of supervisory, global, and local control. Block diagrams are presented of proposed controllers and selected experimental and simulation-study results are shown. In addition, a history is given of the MIT program on reactor digital control

Use of Self-Monitoring to Maintain Program Fidelity of Multi-Tiered Interventions

Science.gov (United States)

Nelson, J. Ron; Oliver, Regina M.; Hebert, Michael A.; Bohaty, Janet

2015-01-01

Multi-tiered system of supports represents one of the most significant advancements in improving the outcomes of students for whom typical instruction is not effective. While many practices need to be in place to make multi-tiered systems of support effective, accurate implementation of evidence-based practices by individuals at all tiers is…

Evolution of the ATLAS data and computing model for a Tier2 in the EGI infrastructure

CERN Document Server

Fernández Casaní, A; The ATLAS collaboration; González de la Hoz, S; Salt Cairols, J; Fassi, F; Kaci, M; Lamas, A; Oliver, E; Sánchez, J; Sánchez, V

2012-01-01

Since the start of the LHC pp collisions in 2010, the ATLAS computing model has moved from a more strict design, where every Tier2 had a liaison and a network dependence from a Tier1, to a more meshed approach where every cloud could be connected. Evolution of ATLAS data models requires changes in ATLAS Tier2s policy for the data replication, dynamic data caching and remote data access. It also requires rethinking the network infrastructure to enable any Tier2 and associated Tier3 to easily connect to any Tier1 or Tier2. Tier2s are becoming more and more important in the ATLAS computing model as it allows more data to be readily accessible for analysis jobs to all users, independently of their geographical location. The Tier2s disk space has been reserved for real, simulated, calibration and alignment, group, and user data. A buffer disk space is needed for input and output data for simulations jobs. Tier2s are going to be used more efficiently. In this way Tier1s and Tier2s are becoming more equivalent for t...

Development of high temperature gas cooled reactor in China

Energy Technology Data Exchange (ETDEWEB)

Guo, Wentao [Paul Scherrer Institute, Villigen (Switzerland). Dept. of Nuclear Energy and Safety; Schorer, Michael [Swiss Nuclear Forum, Olten (Switzerland)

2018-02-15

High temperature gas cooled reactor (HTGR) is one of the six Generation IV reactor types put forward by Generation IV International Forum (GIF) in 2002. This type of reactor has high outlet temperature. It uses Helium as coolant and graphite as moderator. Pebble fuel and ceramic reactor core are adopted. Inherit safety, good economy, high generating efficiency are the advantages of HTGR. According to the comprehensive evaluation from the international nuclear community, HTGR has already been given the priority to the research and development for commercial use. A demonstration project of the High Temperature Reactor-Pebble-�bed Modules (HTR-PM) in Shidao Bay nuclear power plant in China is under construction. In this paper, the development history of HTGR in China and the current situation of HTR-PM will be introduced. The experiences from China may be taken as a reference by the international nuclear community.

Developing the Capacity to Implement Tier 2 and Tier 3 Supports: How Do We Support Our Faculty and Staff in Preparing for Sustainability?

Science.gov (United States)

Oakes, Wendy Peia; Lane, Kathleen Lynne; Germer, Kathryn A.

2014-01-01

School-site and district-level leadership teams rely on the existing knowledge base to select, implement, and evaluate evidence-based practices meeting students' multiple needs within the context of multitiered systems of support. The authors focus on the stages of implementation science as applied to Tier 2 and Tier 3 supports; the…

CMS tier structure and operation of the experiment-specific tasks in Germany

International Nuclear Information System (INIS)

Nowack, A

2008-01-01

In Germany, several university institutes and research centres take part in the CMS experiment. Concerning the data analysis, a couple of computing centres at different Tier levels, ranging from Tier 1 to Tier 3, exists at these places. The German Tier 1 centre GridKa at the research centre at Karlsruhe serves all four LHC experiments as well as four non-LHC experiments. With respect to the CMS experiment, GridKa is mainly involved in central tasks. The Tier 2 centre in Germany consists of two sites, one at the research centre DESY at Hamburg and one at RWTH Aachen University, forming a federated Tier 2 centre. Both parts cover different aspects of a Tier 2 centre. The German Tier 3 centres are located at the research centre DESY at Hamburg, at RWTH Aachen University, and at the University of Karlsruhe. Furthermore the building of a German user analysis facility is planned. Since the CMS community in German is rather small, a good cooperation between the different sites is essential. This cooperation includes physical topics as well as technical and operational issues. All available communication channels such as email, phone, monthly video conferences, and regular personal meetings are used. For example, the distribution of data sets is coordinated globally within Germany. Also the CMS-specific services such as the data transfer tool PhEDEx or the Monte Carlo production are operated by people from different sites in order to spread the knowledge widely and increase the redundancy in terms of operators

A `big-mac` high converting water reactor

Energy Technology Data Exchange (ETDEWEB)

Ronen, Y; Dali, Y [Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Nuclear Engineering

1996-12-01

Currently an effort is being made to get rid of plutonium. Therefore, at this time, a scientific study of a high converting reactor seems to be out of place. However , it is our opinion that the future of nuclear energy lies, among other things in the clever utilization of plutonium. It is also our opinion that one of the best ways to utilize plutonium is in high converting water reactors (authors).

Evolution of the Atlas data and computing model for a Tier-2 in the EGI infrastructure

CERN Document Server

Fernandez, A; The ATLAS collaboration; AMOROS, G; VILLAPLANA, M; FASSI, F; KACI, M; LAMAS, A; OLIVER, E; SALT, J; SANCHEZ, J; SANCHEZ, V

2012-01-01

ABSTRAC ISCG 2012 Evolution of the Atlas data and computing model for a Tier2 in the EGI infrastructure During last years the Atlas computing model has moved from a more strict design, where every Tier2 had a liaison and a network dependence from a Tier1, to a more meshed approach where every cloud could be connected. Evolution of ATLAS data models requires changes in ATLAS Tier2s policy for the data replication, dynamic data caching and remote data access. It also requires rethinking the network infrastructure to enable any Tier2 and associated Tier3 to easily connect to any Tier1 or Tier2. Tier2s are becoming more and more important in the ATLAS computing model as it allows more data to be readily accessible for analysis jobs to all users, independently of their geographical location. The Tier2s disk space has been reserved for real, simulated, calibration and alignment, group, and user data. A buffer disk space is needed for input and output data for simulations jobs. Tier2s are going to be used more effic...

High aspect ratio catalytic reactor and catalyst inserts therefor

Science.gov (United States)

Lin, Jiefeng; Kelly, Sean M.

2018-04-10

The present invention relates to high efficient tubular catalytic steam reforming reactor configured from about 0.2 inch to about 2 inch inside diameter high temperature metal alloy tube or pipe and loaded with a plurality of rolled catalyst inserts comprising metallic monoliths. The catalyst insert substrate is formed from a single metal foil without a central supporting structure in the form of a spiral monolith. The single metal foil is treated to have 3-dimensional surface features that provide mechanical support and establish open gas channels between each of the rolled layers. This unique geometry accelerates gas mixing and heat transfer and provides a high catalytic active surface area. The small diameter, high aspect ratio tubular catalytic steam reforming reactors loaded with rolled catalyst inserts can be arranged in a multi-pass non-vertical parallel configuration thermally coupled with a heat source to carry out steam reforming of hydrocarbon-containing feeds. The rolled catalyst inserts are self-supported on the reactor wall and enable efficient heat transfer from the reactor wall to the reactor interior, and lower pressure drop than known particulate catalysts. The heat source can be oxygen transport membrane reactors.

AUDIOME: a tiered exome sequencing-based comprehensive gene panel for the diagnosis of heterogeneous nonsyndromic sensorineural hearing loss.

Science.gov (United States)

Guan, Qiaoning; Balciuniene, Jorune; Cao, Kajia; Fan, Zhiqian; Biswas, Sawona; Wilkens, Alisha; Gallo, Daniel J; Bedoukian, Emma; Tarpinian, Jennifer; Jayaraman, Pushkala; Sarmady, Mahdi; Dulik, Matthew; Santani, Avni; Spinner, Nancy; Abou Tayoun, Ahmad N; Krantz, Ian D; Conlin, Laura K; Luo, Minjie

2018-03-29

PurposeHereditary hearing loss is highly heterogeneous. To keep up with rapidly emerging disease-causing genes, we developed the AUDIOME test for nonsyndromic hearing loss (NSHL) using an exome sequencing (ES) platform and targeted analysis for the curated genes.MethodsA tiered strategy was implemented for this test. Tier 1 includes combined Sanger and targeted deletion analyses of the two most common NSHL genes and two mitochondrial genes. Nondiagnostic tier 1 cases are subjected to ES and array followed by targeted analysis of the remaining AUDIOME genes.ResultsES resulted in good coverage of the selected genes with 98.24% of targeted bases at >15 ×. A fill-in strategy was developed for the poorly covered regions, which generally fell within GC-rich or highly homologous regions. Prospective testing of 33 patients with NSHL revealed a diagnosis in 11 (33%) and a possible diagnosis in 8 cases (24.2%). Among those, 10 individuals had variants in tier 1 genes. The ES data in the remaining nondiagnostic cases are readily available for further analysis.ConclusionThe tiered and ES-based test provides an efficient and cost-effective diagnostic strategy for NSHL, with the potential to reflex to full exome to identify causal changes outside of the AUDIOME test.Genetics in Medicine advance online publication, 29 March 2018; doi:10.1038/gim.2018.48.

Cascade: a high-efficiency ICF power reactor

International Nuclear Information System (INIS)

Pitts, J.H.

1985-01-01

Cascade attains a net power-plant efficiency of 49% and its cost is competitive with high-temperature gas-cooled reactor, pressurized-water reactor, and coal-fired power plants. The Cascade reactor and blanket are made of ceramic materials and activation is 6 times less than that of the MARS Tandem Mirror Reactor operating at comparable power. Hands-on maintenance of the heat exchangers is possible one day after shutdown. Essentially all tritium is recovered in the vacuum system, with the remainder recovered from the helium power conversion loop. Tritium leakage external to the vacuum system and power conversion loop is only 0.03 Ci/d

A high temperature reactor for ship propulsion

International Nuclear Information System (INIS)

Lobet, P.; Seigel, R.; Thompson, A.C.; Beadnell, R.M.; Beeley, P.A.

2002-01-01

The initial thermal hydraulic and physics design of a high temperature gas cooled reactor for ship propulsion is described. The choice of thermodynamic cycle and thermal power is made to suit the marine application. Several configurations of a Helium cooled, Graphite moderated reactor are then analysed using the WIMS and MONK codes from AEA Technology. Two geometries of fuel elements formed using micro spheres in prismatic blocks, and various arrangements of control rods and poison rods are examined. Reactivity calculations through life are made and a pattern of rod insertion to flatten the flux is proposed and analysed. Thermal hydraulic calculations are made to find maximum fuel temperature under high power with optimized flow distribution. Maximum temperature after loss of flow and temperatures in the reactor vessel are also computed. The temperatures are significantly below the known limits for the type of fuel proposed. It is concluded that the reactor can provide the required power and lifetime between refueling within likely space and weight constraints. (author)

Frontier: High Performance Database Access Using Standard Web Components in a Scalable Multi-Tier Architecture

International Nuclear Information System (INIS)

Kosyakov, S.; Kowalkowski, J.; Litvintsev, D.; Lueking, L.; Paterno, M.; White, S.P.; Autio, Lauri; Blumenfeld, B.; Maksimovic, P.; Mathis, M.

2004-01-01

A high performance system has been assembled using standard web components to deliver database information to a large number of broadly distributed clients. The CDF Experiment at Fermilab is establishing processing centers around the world imposing a high demand on their database repository. For delivering read-only data, such as calibrations, trigger information, and run conditions data, we have abstracted the interface that clients use to retrieve data objects. A middle tier is deployed that translates client requests into database specific queries and returns the data to the client as XML datagrams. The database connection management, request translation, and data encoding are accomplished in servlets running under Tomcat. Squid Proxy caching layers are deployed near the Tomcat servers, as well as close to the clients, to significantly reduce the load on the database and provide a scalable deployment model. Details the system's construction and use are presented, including its architecture, design, interfaces, administration, performance measurements, and deployment plan

Design and development of gas turbine high temperature reactor 300

International Nuclear Information System (INIS)

Kunitomi, Kazuhiko; Katanishi, Shoji; Takada, Shoji; Yan, Xing; Takizuka, Takakazu

2003-01-01

JAERI (Japan Atomic Energy Research Institute) has been designing a Japan's original gas turbine high temperature reactor, GTHTR300 (Gas Turbine High Temperature Reactor 300). The greatly simplified design based on salient features of the HTGR (High Temperature Gas-cooled reactor) with a closed helium gas turbine enables the GTHTR300 a high efficient and economically competitive reactor to be deployed in early 2010s. Also, the GTHTR300 fully taking advantage of various experiences accumulated in design, construction and operation of the HTTR (High Temperature Engineering Test Reactor) and fossil gas turbine systems reduces technological development concerning a reactor system and electric generation system. Original features of this system are core design with two-year refueling interval, conventional steel material usage for a reactor pressure vessel, innovative plant flow scheme and horizontally installed gas turbine unit. Due to these salient features, the capital cost of the GTHTR300 is less than a target cost of 200 thousands Yen/kWe, and the electric generation cost is close to a target cost of 4 Yen/kWh. This paper describes the original design features focusing on reactor core design, fuel design, in-core structure design and reactor pressure vessel design except PCU design. Also, R and D for developing the power conversion unit is briefly described. The present study is entrusted from the Ministry of Education, Culture, Sports, Science and Technology of Japan. (author)

Preprocessing in a Tiered Sensor Network for Habitat Monitoring

Directory of Open Access Journals (Sweden)

Hanbiao Wang

2003-03-01

Full Text Available We investigate task decomposition and collaboration in a two-tiered sensor network for habitat monitoring. The system recognizes and localizes a specified type of birdcalls. The system has a few powerful macronodes in the first tier, and many less powerful micronodes in the second tier. Each macronode combines data collected by multiple micronodes for target classification and localization. We describe two types of lightweight preprocessing which significantly reduce data transmission from micronodes to macronodes. Micronodes classify events according to their cross-zero rates and discard irrelevant events. Data about events of interest is reduced and compressed before being transmitted to macronodes for target localization. Preliminary experiments illustrate the effectiveness of event filtering and data reduction at micronodes.

Study of trans-uranian incineration in molten salt reactor; Etude de l'incineration des transuraniens en reacteur a sel fondu

Energy Technology Data Exchange (ETDEWEB)

Valade, M

2000-10-27

With the emergence of new options for nuclear power, molten salt reactors are envisaged for waste management. The aim of this thesis is to show how molten salt reactors can help to solve the transuranics issue. Their high versatility regarding to isotopic vector allows to accommodate large fractions of minor actinides as compared to solid fuel system. In this thesis, a neutronics study of molten salt reactors, MSR, has been conducted. For this purpose, two reference systems were considered, TIER1 and AMSTER. In the case of TIER1, an optimisation was made to reach an equilibrium. The analysis of both systems showed the main characteristics of MSR: their link to chemistry and on line reprocessing. In this work, several methods to drive the system to a state of equilibrium have been implemented and compared. During this process the isotopic composition and neutron spectrum, thus the nuclear reaction cross sections, vary tremendously. It is essential to take these evolutions into account in order to accurately estimate the equilibrium state. This has been accomplished inside the multi-recycling procedure we set with ERANOS. A dedicated calculation schema has been realized to simulate superthermal systems with this computation code. These results were checked through a benchmark against other computer codes. Then, with multi-recycling method, several molten salt systems have been compared in order to define the optimal reactor for transuranics incineration. Nevertheless, a final choice can not only be done using only neutronics characteristics since chemistry and thermal-hydraulics constraints are really important for MSR. Moreover, a complete safety study would be required. (author)

High temperature fast reactor for hydrogen production in Brazil

International Nuclear Information System (INIS)

Nascimento, Jamil A. do; Ono, Shizuca; Guimaraes, Lamartine N.F.

2008-01-01

The main nuclear reactors technology for the Generation IV, on development phase for utilization after 2030, is the fast reactor type with high temperature output to improve the efficiency of the thermo-electric conversion process and to enable applications of the generated heat in industrial process. Currently, water electrolysis and thermo chemical cycles using very high temperature are studied for large scale and long-term hydrogen production, in the future. With the possible oil scarcity and price rise, and the global warming, this application can play an important role in the changes of the world energy matrix. In this context, it is proposed a fast reactor with very high output temperature, ∼ 1000 deg C. This reactor will have a closed fuel cycle; it will be cooled by lead and loaded with nitride fuel. This reactor may be used for hydrogen, heat and electricity production in Brazil. It is discussed a development strategy of the necessary technologies and some important problems are commented. The proposed concept presents characteristics that meet the requirements of the Generation IV reactor class. (author)

ATLAS Tier-2 at the Compute Resource Center GoeGrid in Göttingen

Science.gov (United States)

Meyer, Jörg; Quadt, Arnulf; Weber, Pavel; ATLAS Collaboration

2011-12-01

GoeGrid is a grid resource center located in Göttingen, Germany. The resources are commonly used, funded, and maintained by communities doing research in the fields of grid development, computer science, biomedicine, high energy physics, theoretical physics, astrophysics, and the humanities. For the high energy physics community, GoeGrid serves as a Tier-2 center for the ATLAS experiment as part of the world-wide LHC computing grid (WLCG). The status and performance of the Tier-2 center is presented with a focus on the interdisciplinary setup and administration of the cluster. Given the various requirements of the different communities on the hardware and software setup the challenge of the common operation of the cluster is detailed. The benefits are an efficient use of computer and personpower resources.

Prospective Environmental Risk Assessment for Sediment-Bound Organic Chemicals: A Proposal for Tiered Effect Assessment.

Science.gov (United States)

Diepens, Noël J; Koelmans, Albert A; Baveco, Hans; van den Brink, Paul J; van den Heuvel-Greve, Martine J; Brock, Theo C M

A broadly accepted framework for prospective environmental risk assessment (ERA) of sediment-bound organic chemicals is currently lacking. Such a framework requires clear protection goals, evidence-based concepts that link exposure to effects and a transparent tiered-effect assessment. In this paper, we provide a tiered prospective sediment ERA procedure for organic chemicals in sediment, with a focus on the applicable European regulations and the underlying data requirements. Using the ecosystem services concept, we derived specific protection goals for ecosystem service providing units: microorganisms, benthic algae, sediment-rooted macrophytes, benthic invertebrates and benthic vertebrates. Triggers for sediment toxicity testing are discussed.We recommend a tiered approach (Tier 0 through Tier 3). Tier-0 is a cost-effective screening based on chronic water-exposure toxicity data for pelagic species and equilibrium partitioning. Tier-1 is based on spiked sediment laboratory toxicity tests with standard benthic test species and standardised test methods. If comparable chronic toxicity data for both standard and additional benthic test species are available, the Species Sensitivity Distribution (SSD) approach is a more viable Tier-2 option than the geometric mean approach. This paper includes criteria for accepting results of sediment-spiked single species toxicity tests in prospective ERA, and for the application of the SSD approach. We propose micro/mesocosm experiments with spiked sediment, to study colonisation success by benthic organisms, as a Tier-3 option. Ecological effect models can be used to supplement the experimental tiers. A strategy for unifying information from various tiers by experimental work and exposure-and effect modelling is provided.

The evolving role of Tier2s in ATLAS with the new Computing and Data Distribution model

International Nuclear Information System (INIS)

González de la Hoz, S

2012-01-01

Originally the ATLAS Computing and Data Distribution model assumed that the Tier-2s should keep on disk collectively at least one copy of all “active” AOD and DPD datasets. Evolution of ATLAS Computing and Data model requires changes in ATLAS Tier-2s policy for the data replication, dynamic data caching and remote data access. Tier-2 operations take place completely asynchronously with respect to data taking. Tier-2s do simulation and user analysis. Large-scale reprocessing jobs on real data are at first taking place mostly at Tier-1s but will progressively be shared with Tier-2s as well. The availability of disk space at Tier-2s is extremely important in the ATLAS Computing model as it allows more data to be readily accessible for analysis jobs to all users, independently of their geographical location. The Tier-2s disk space has been reserved for real, simulated, calibration and alignment, group, and user data. A buffer disk space is needed for input and output data for simulations jobs. Tier-2s are going to be used more efficiently. In this way Tier-1s and Tier-2s are becoming more equivalent for the network and the hierarchy of Tier-1, 2 is less strict. This paper presents the usage of Tier-2s resources in different Grid activities, caching of data at Tier-2s, and their role in the analysis in the new ATLAS Computing and Data model.

Systems and methods for enhancing isolation of high-temperature reactor containments

Energy Technology Data Exchange (ETDEWEB)

Peterson, Per F.

2017-09-26

A high-temperature containment-isolation system for transferring heat from a nuclear reactor containment to a high-pressure heat exchanger is presented. The system uses a high-temperature, low-volatility liquid coolant such as a molten salt or a liquid metal, where the coolant flow path provides liquid free surfaces a short distance from the containment penetrations for the reactor hot-leg and the cold-leg, where these liquid free surfaces have a cover gas maintained at a nearly constant pressure and thus prevent high-pressures from being transmitted into the reactor containment, and where the reactor vessel is suspended within a reactor cavity with a plurality of refractory insulator blocks disposed between an actively cooled inner cavity liner and the reactor vessel.

Onbekend maakt onbemind : De One-Tier Board bij Royal Dutch Shell - Geleerde lessen

NARCIS (Netherlands)

dr. Stefan Peij; Michiel Brandjes

2012-01-01

Op 1 januari 2013 wordt de Wet Bestuur en Toezicht naar verwachting van kracht1. Na invoering van deze wet kunnen bedrijven gemakkelijker kiezen uit de one-tier board en de two-tier board als bestuursmodel. Shell heeft in 2005 het one-tier model ingevoerd en kan dus al de eerste balans opmaken.

Towards a theory of tiered testing.

Science.gov (United States)

Hansson, Sven Ove; Rudén, Christina

2007-06-01

Tiered testing is an essential part of any resource-efficient strategy for the toxicity testing of a large number of chemicals, which is required for instance in the risk management of general (industrial) chemicals, In spite of this, no general theory seems to be available for the combination of single tests into efficient tiered testing systems. A first outline of such a theory is developed. It is argued that chemical, toxicological, and decision-theoretical knowledge should be combined in the construction of such a theory. A decision-theoretical approach for the optimization of test systems is introduced. It is based on expected utility maximization with simplified assumptions covering factual and value-related information that is usually missing in the development of test systems.

Use of sup(233)U for high flux reactors

International Nuclear Information System (INIS)

Sekimoto, Hiroshi; Liem, P.H.

1991-01-01

The feasibility design study on the graphite moderated gas cooled reactor as a high flux reactor has been performed. The core of the reactor is equipped with two graphite reflectors, i.e., the inner reflector and the outer reflector. The highest value of the thermal neutron flux and moderately high thermal neutron flux are expected to be achieved in the inner reflector region and in the outer reflector region respectively. This reactor has many merits comparing to the conventional high flux reactors. It has the inherent safety features associated with the modular high temperature reactors. Since the core is composed with pebble bed, the on-power refueling can be performed and the experiment time can be chosen as long as necessary. Since the thermal-to-fast flux ratio is large, the background neutron level is low and material damage induced by fast neutrons are small. The calculation was performed using a four groups diffusion approximation in a one-dimensional spherical geometry and a two-dimensional cylindrical geometry. By choosing the optimal values of the core-reflector geometrical parameters and moderator-to-fuel atomic density, high thermal neutron flux can be obtained. Because of the thermal neutron flux can be obtained. Because of the thermal design constraint, however, this design will produce a relatively large core volume (about 10 7 cc) and consequently a higher reactor power (100 MWth). Preliminary calculational results show that with an average power density of only 10 W/cc, maximum thermal neutron flux of 10 15 cm -2 s -1 can be achieved in the inner reflector. The eta value of 233 U is larger than 235 U. By introducing 233 U as the fissile material for this reactor, the thermal neutron flux level can be increased by about 15%. (author). 3 refs., 2 figs., 4 tabs

Reactor vessel dismantling at the high flux materials testing reactor Petten

International Nuclear Information System (INIS)

Tas, A.; Teunissen, G.

1986-01-01

The project of replacing the reactor vessel of the high flux materials testing reactor (HFR) originated in 1974 when results of several research programs confirmed severe neutron embrittlement of aluminium alloys suggesting a limited life of the existing facility. This report describes the dismantling philosophy and organisation, the design of special underwater equipment, the dismantling of the reactor vessel and thermal column, and the conditioning and shielding activities resulting in a working area for the installation of the new vessel with no access limitations due to radiation. Finally an overview of the segmentation, waste disposal and radiation exposure is given. The total dismantling, segmentation and conditioning activities resulted in a total collective radiation dose of 300 mSv. (orig.) [de

77 FR 71481 - Publication of the Tier 2 Tax Rates

Science.gov (United States)

2012-11-30

... DEPARTMENT OF THE TREASURY Internal Revenue Service Publication of the Tier 2 Tax Rates AGENCY... tax rates for calendar year 2013 as required by section 3241(d) of the Internal Revenue Code (26 U.S.C. 3241). Tier 2 taxes on railroad employees, employers, and employee representatives are one source of...

Study of trans-uranian incineration in molten salt reactor; Etude de l'incineration des transuraniens en reacteur a sel fondu

Energy Technology Data Exchange (ETDEWEB)

Valade, M

2000-10-27

With the emergence of new options for nuclear power, molten salt reactors are envisaged for waste management. The aim of this thesis is to show how molten salt reactors can help to solve the transuranics issue. Their high versatility regarding to isotopic vector allows to accommodate large fractions of minor actinides as compared to solid fuel system. In this thesis, a neutronics study of molten salt reactors, MSR, has been conducted. For this purpose, two reference systems were considered, TIER1 and AMSTER. In the case of TIER1, an optimisation was made to reach an equilibrium. The analysis of both systems showed the main characteristics of MSR: their link to chemistry and on line reprocessing. In this work, several methods to drive the system to a state of equilibrium have been implemented and compared. During this process the isotopic composition and neutron spectrum, thus the nuclear reaction cross sections, vary tremendously. It is essential to take these evolutions into account in order to accurately estimate the equilibrium state. This has been accomplished inside the multi-recycling procedure we set with ERANOS. A dedicated calculation schema has been realized to simulate superthermal systems with this computation code. These results were checked through a benchmark against other computer codes. Then, with multi-recycling method, several molten salt systems have been compared in order to define the optimal reactor for transuranics incineration. Nevertheless, a final choice can not only be done using only neutronics characteristics since chemistry and thermal-hydraulics constraints are really important for MSR. Moreover, a complete safety study would be required. (author)

Experience running a distributed Tier-2 in Spain for the ATLAS experiment

International Nuclear Information System (INIS)

March, L; Hoz, S Gonzales de la; Kaci, M; Fassi, F; Fernandez, A; Lamas, A; Salt, J; Sanchez, J; Peso, J del; Fernandez, P; Munoz, L; Pardo, J; Espinal, X; Garitaonandia, H; Mir, M L; Nadal, J; Pacheco, A; Shuskov, S

2008-01-01

The main role of the Tier-2s is to provide computing resources for production of physics simulated events and distributed data analysis. The Spanish ATLAS Tier-2 is geographically distributed among three HEP institutes: IFAE (Barcelona), IFIC (Valencia) and UAM (Madrid). Currently it has a computing power of 430 kSI2K CPU, a disk storage capacity of 87 TB and a network bandwidth, connecting the three sites and the nearest Tier-1 (PIC), of 1 Gb/s. These resources will be increased according to the ATLAS Computing Model with time in parallel to those of all ATLAS Tier-2s. Since 2002, it has been participating into the different Data Challenge exercises. Currently, it is achieving around 1.5% of the whole ATLAS collaboration production in the framework of the Computing System Commissioning exercise. A distributed data management is also arising as an important issue in the daily activities of the Tier-2. The distribution in three sites has shown to be useful due to an increasing service redundancy, a faster solution of problems, the share of computing expertise and know-how. Experience gained running the distributed Tier-2 in order to be ready at the LHC start-up will be presented

Using Brief Experimental Analysis to Intensify Tier 3 Reading Interventions

Science.gov (United States)

Coolong-Chaffin, Melissa; Wagner, Dana

2015-01-01

As implementation of multi-tiered systems of support becomes common practice across the nation, practitioners continue to need strategies for intensifying interventions and supports for the subset of students who fail to make adequate progress despite strong programs at Tiers 1 and 2. Experts recommend making several changes to the structure and…

RHTF 2, a 1200 MWe high temperature reactor

International Nuclear Information System (INIS)

Brisbois, Jacques

1978-01-01

After having adapted to French conditions the 1160 MWe G.A.C. reactor, Commissariat a l'Energie Atomique and French Industry have decided to design an High Temperature Reactor 1200 MWe based on the G.A.C. technology and taking into account the point of view of Electricite de France and the experience of C.E.A. and industry on the gas cooled reactor technology. The main objective of this work is to produce a reactor design having a low technical risk, good operability, with an emphasis on the safety aspects easing the licensing problems

Tiering Effects in Third-party Logistics: A First-tier Buyer Perspective

OpenAIRE

Vainionpää, Mikael M.

2010-01-01

This doctoral dissertation takes a buy side perspective to third-party logistics (3PL) providers’ service tiering by applying a linear serial dyadic view to transactions. It takes its point of departure not only from the unalterable focus on the dyad levels as units of analysis and how to manage them, but also the characteristics both creating and determining purposeful conditions for a longer duration. A conceptual framework is proposed and evaluated on its ability to capture logistics se...

High-temperature reactor developments in the Netherlands

International Nuclear Information System (INIS)

Schram, R.P.C.; Cordfunke, E.H.P.; Heek, A.I. van.

1996-01-01

The high-temperature reactor development in the Netherland is embedded in the WHITE reactor program, in which several Dutch research institutes and engineering companies participate. The activities within the WHITE program are focused on the development of a small scale HTS for combined heat and power generation. In 1995, design choices for a pebble bed reactor were made at ECN. The first concept HTR will gave a closed cycle helium turbine and a power level of 40 MWth. It is intended to make the market introduction of a commercially competitive HTR feasible. The design will be an optimization of the Peu-a-Peu (PAP) concept of KFA Juelich. Computer codes necessary for the evaluation of reactor physics aspects of this reactor are developed in cooperation with international partners. An evaluation of a 20 MWth PAP concept showed that the maximum fuel termmperature after depressurization does not exceed 1300 C. (orig.)

Reactor physics and reactor strategy investigations into the fissionable material economy of the thorium and uranium cycle in fast breeder reactors and high temperature reactors

International Nuclear Information System (INIS)

Schikorr, W.M.

In this work the properties governing the fissionable material economy of the uranium and thorium cycles are investigated for the advanced reactor types currently under development - the fast breeder reactor (FBR) and the high temperature reactor (HTR) - from the point of view of the optimum utilization of the available nuclear fuel reserves and the continuance of supply of these reserves. For this purpose, the two reactor types are first of all considered individually and are subsequently discussed as a complementary overall system

IAEA high temperature gas-cooled reactor activities

International Nuclear Information System (INIS)

Kendall, J.M.

2000-01-01

The IAEA activities on high temperature gas-cooled reactors are conducted with the review and support of the Member states, primarily through the International Working Group on Gas-Cooled Reactors (IWG-GCR). This paper summarises the results of the IAEA gas-cooled reactor project activities in recent years along with ongoing current activities through a review of Co-ordinated Research Projects (CRPs), meetings and other international efforts. A series of three recently completed CRPs have addressed the key areas of reactor physics for LEU fuel, retention of fission products and removal of post shutdown decay heat through passive heat transport mechanisms. These activities along with other completed and ongoing supporting CRPs and meetings are summarised with reference to detailed documentation of the results. (authors)

IAEA high temperature gas cooled reactor activities

International Nuclear Information System (INIS)

Kendall, J.M.

2001-01-01

IAEA activities on high temperature gas cooled reactors are conducted with the review and support of Member States, primarily through the International Working Group on Gas Cooled Reactors (IWGGCR). This paper summarises the results of the IAEA gas cooled reactor project activities in recent years along with ongoing current activities through a review of Co-ordinated Research Projects (CRPs), meetings and other international efforts. A series of three recently completed CRPs have addressed the key areas of reactor physics for LEU fuel, retention of fission products, and removal of post shutdown decay heat through passive heat transport mechanisms. These activities along with other completed and ongoing supporting CRPs and meetings are summarised with reference to detailed documentation of the results. (author)

Comparison of tiered formularies and reference pricing policies: a systematic review.

Science.gov (United States)

Morgan, Steve; Hanley, Gillian; Greyson, Devon

2009-01-01

To synthesize methodologically comparable evidence from the published literature regarding the outcomes of tiered formularies and therapeutic reference pricing of prescription drugs. We searched the following electronic databases: ABI/Inform, CINAHL, Clinical Evidence, Digital Dissertations & Theses, Evidence-Based Medicine Reviews (which incorporates ACP Journal Club, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Cochrane Methodology Register, Database of Abstracts of Reviews of Effectiveness, Health Technology Assessments and NHS Economic Evaluation Database), EconLit, EMBASE, International Pharmaceutical Abstracts, MEDLINE, PAIS International and PAIS Archive, and the Web of Science. We also searched the reference lists of relevant articles and several grey literature sources. We sought English-language studies published from 1986 to 2007 that examined the effects of either therapeutic reference pricing or tiered formularies, reported on outcomes relevant to patient care and cost-effectiveness, and employed quantitative study designs that included concurrent or historical comparison groups. We abstracted and assessed potentially appropriate articles using a modified version of the data abstraction form developed by the Cochrane Effective Practice and Organisation of Care Group. From an initial list of 2964 citations, 12 citations (representing 11 studies) were deemed eligible for inclusion in our review: 3 studies (reported in 4 articles) of reference pricing and 8 studies of tiered formularies. The introduction of reference pricing was associated with reduced plan spending, switching to preferred medicines, reduced overall drug utilization and short-term increases in the use of physician services. Reference pricing was not associated with adverse health impacts. The introduction of tiered formularies was associated with reduced plan expenditures, greater patient costs and increased rates of non-compliance with

Summary of ORNL high-temperature gas-cooled reactor program

International Nuclear Information System (INIS)

Kasten, P.R.

1981-01-01

Oak Ridge National Laboratory (ORNL) efforts on the High-Temperature Gas-Cooled Reactor (HTGR) Program have been on HTGR fuel development, fission product and coolant chemistry, prestressed concrete reactor vessel (PCRV) studies, materials studies, graphite development, reactor physics and shielding studies, application assessments and evaluations and selected component testing

High power density reactors based on direct cooled particle beds

Science.gov (United States)

Powell, J. R.; Horn, F. L.

Reactors based on direct cooled High Temperature Gas Cooled Reactor (HTGR) type particle fuel are described. The small diameter particle fuel is packed between concentric porous cylinders to make annular fuel elements, with the inlet coolant gas flowing inwards. Hot exit gas flows out along the central channel of each element. Because of the very large heat transfer area in the packed beds, power densities in particle bed reactors (PBRs) are extremely high resulting in compact, lightweight systems. Coolant exit temperatures are high, because of the ceramic fuel temperature capabilities, and the reactors can be ramped to full power and temperature very rapidly. PBR systems can generate very high burst power levels using open cycle hydrogen coolant, or high continuous powers using closed cycle helium coolant. PBR technology is described and development requirements assessed.

Australia's new high performance research reactor

International Nuclear Information System (INIS)

Miller, R.; Abbate, P.M.

2003-01-01

A contract for the design and construction of the Replacement Research Reactor was signed in July 2000 between ANSTO and INVAP from Argentina. Since then the detailed design has been completed, a construction authorization has been obtained, and construction has commenced. The reactor design embodies modern safety thinking together with innovative solutions to ensure a highly safe and reliable plant. Also significant effort has been placed on providing the facility with diverse and ample facilities to maximize its use for irradiating material for radioisotope production as well as providing high neutron fluxes for neutron beam research. The project management organization and planing is commensurate with the complexity of the project and the number of players involved. (author)

Medium-size high-temperature gas-cooled reactor

International Nuclear Information System (INIS)

Peinado, C.O.; Koutz, S.L.

1980-08-01

This report summarizes high-temperature gas-cooled reactor (HTGR) experience for the 40-MW(e) Peach Bottom Nuclear Generating Station of Philadelphia Electric Company and the 330-MW(e) Fort St. Vrain Nuclear Generating Station of the Public Service Company of Colorado. Both reactors are graphite moderated and helium cooled, operating at approx. 760 0 C (1400 0 F) and using the uranium/thorium fuel cycle. The plants have demonstrated the inherent safety characteristics, the low activation of components, and the high efficiency associated with the HTGR concept. This experience has been translated into the conceptual design of a medium-sized 1170-MW(t) HTGR for generation of 450 MW of electric power. The concept incorporates inherent HTGR safety characteristics [a multiply redundant prestressed concrete reactor vessel (PCRV), a graphite core, and an inert single-phase coolant] and engineered safety features

The modular high-temperature gas-cooled reactor - a new production reactor

International Nuclear Information System (INIS)

Nulton, J.D.

1990-01-01

One of the reactor concepts being considered for application as a new production reactor (NPR) is a 350-MW(thermal) modular high-temperature gas-cooled reactor (MHTGR). The proposed MHTGR-NPR is based on the design of the commercial MHTGR and is being developed by a team that includes General Atomics and Combustion Engineering. The proposed design includes four modules combined into a production block that includes a shared containment, a spent-fuel storage facility, and other support facilities. The MHTGR has a helium-cooled, graphite-moderated, graphite-reflected annular core formed from prismatic graphite fuel blocks. The MHTGR fuel consists of highly enriched uranium oxycarbide (UCO) microsphere fuel particles that are coated with successive layers of pyrolytic carbon (PyC) and silicon carbide (SiC). Tritium-producing targets consist of enriched 6 Li aluminate microsphere target particles that are coated with successive layers of PyC and SiC similar to the fuel microspheres. Normal reactivity control is implemented by articulated control rods that can be inserted into channels in the inner and outer reflector blocks. Shutdown heat removal is accomplished by a single shutdown heat exchanger and electric motor-driven circulator located in the bottom of the reactor vessel. Current plans are to stack spent fuel elements in dry, helium-filled, water-cooled wells and store them for ∼1 yr before reprocessing. All phases of MHTGR fuel reprocessing have been demonstrated

Production of high-specific activity radionuclides using SM high-flux reactor

International Nuclear Information System (INIS)

Karelin, Ye.A.; Toporov, Yu.G.; Filimonov, V.T.; Vakhetov, F.Z.; Tarasov, V.A.; Kuznetsov, R.A.; Lebedev, V.M.; Andreev, O.I.; Melnik, M.I.; Gavrilov, V.D.

1997-01-01

The development of High Specific Activity (HSA) radionuclides production technologies is one of the directions of RIAR activity, and the high flux research reactor SM, having neutron flux density up to 2.10 15 cm -2 s 1 in a wide range of neutron spectra hardness, plays the principal role in this development. The use of a high-flux reactor for radionuclide production provides the following advantages: production of radionuclides with extremely high specific activity, decreasing of impurities content in irradiated targets (both radioactive and non-radioactive), cost-effective use of expensive isotopically enriched target materials. The production technologies of P-33, Gd-153, W-188, Ni-63, Fe-55,59, Sn-113,117m,119m, Sr- 89, applied in industry, nuclear medicine, research, etc, were developed by RIAR during the last 5-10 years. The research work included the development of calculation procedures for radionuclide reactor accumulation forecast, experimental determination of neutron cross-sections, the development of irradiated materials reprocessing procedures, isolation and purification of radionuclides. The principal results are reviewed in the paper. (authors)

Optimization of HEP Analysis Activities Using a Tier2 Infrastructure

International Nuclear Information System (INIS)

Arezzini, S; Bagliesi, G; Boccali, T; Ciampa, A; Mazzoni, E; Coscetti, S; Sarkar, S; Taneja, S

2012-01-01

While the model for a Tier2 is well understood and implemented within the HEP Community, a refined design for Analysis specific sites has not been agreed upon as clearly. We aim to describe the solutions adopted at the INFN Pisa, the biggest Tier2 in the Italian HEP Community. A Standard Tier2 infrastructure is optimized for Grid CPU and Storage access, while a more interactive oriented use of the resources is beneficial to the final data analysis step. In this step, POSIX file storage access is easier for the average physicist, and has to be provided in a real or emulated way. Modern analysis techniques use advanced statistical tools (like RooFit and RooStat), which can make use of multi core systems. The infrastructure has to provide or create on demand computing nodes with many cores available, above the existing and less elastic Tier2 flat CPU infrastructure. At last, the users do not want to have to deal with data placement policies at the various sites, and hence a transparent WAN file access, again with a POSIX layer, must be provided, making use of the soon-to-be-installed 10 Gbit/s regional lines. Even if standalone systems with such features are possible and exist, the implementation of an Analysis site as a virtual layer over an existing Tier2 requires novel solutions; the ones used in Pisa are described here.

Analysis of internal network requirements for the distributed Nordic Tier-1

DEFF Research Database (Denmark)

Behrmann, G.; Fischer, L.; Gamst, Mette

2010-01-01

The Tier-1 facility operated by the Nordic DataGrid Facility (NDGF) differs significantly from other Tier-1s in several aspects: It is not located at one or a few locations but instead distributed throughout the Nordic, it is not under the governance of a single organisation but but is instead...... build from resources under the control of a number of different national organisations. Being physically distributed makes the design and implementation of the networking infrastructure a challenge. NDGF has its own internal OPN connecting the sites participating in the distributed Tier-1. To assess...

Issues of high-burnup fuel for advanced nuclear reactors

International Nuclear Information System (INIS)

Belac, J.; Milisdoerfer, L.

2004-12-01

A brief description is given of nuclear fuels for Generation III+ and IV reactors, and the major steps needed for a successful implementation of new fuels in prospective types of newly designed power reactors are outlined. The following reactor types are discussed: gas cooled fast reactors, heavy metal (lead) cooled fast reactors, molten salt cooled reactors, sodium cooled fast reactors, supercritical water cooled reactors, and very high temperature reactors. The following are regarded as priority areas for future investigations: (i) spent fuel radiotoxicity; (ii) proliferation volatility; (iii) neutron physics characteristics and inherent safety element assessment; technical and economic analysis of the manufacture of advanced fuels; technical and economic analysis of the fuel cycle back end, possibilities of spent nuclear fuel reprocessing, storage and disposal. In parallel, work should be done on the validation and verification of analytical tools using existing and/or newly acquired experimental data. (P.A.)

Proposed Advanced Reactor Adaptation of the Standard Review Plan NUREG-0800 Chapter 4 (Reactor) for Sodium-Cooled Fast Reactors and Modular High-Temperature Gas-Cooled Reactors

Energy Technology Data Exchange (ETDEWEB)

Belles, Randy [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Poore, III, Willis P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brown, Nicholas R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Flanagan, George F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holbrook, Mark [Idaho National Lab. (INL), Idaho Falls, ID (United States); Moe, Wayne [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sofu, Tanju [Argonne National Lab. (ANL), Argonne, IL (United States)

2017-03-01

This report proposes adaptation of the previous regulatory gap analysis in Chapter 4 (Reactor) of NUREG 0800, Standard Review Plan (SRP) for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR [Light Water Reactor] Edition. The proposed adaptation would result in a Chapter 4 review plan applicable to certain advanced reactors. This report addresses two technologies: the sodium-cooled fast reactor (SFR) and the modular high temperature gas-cooled reactor (mHTGR). SRP Chapter 4, which addresses reactor components, was selected for adaptation because of the possible significant differences in advanced non-light water reactor (non-LWR) technologies compared with the current LWR-based description in Chapter 4. SFR and mHTGR technologies were chosen for this gap analysis because of their diverse designs and the availability of significant historical design detail.

Adaptive data migration scheme with facilitator database and multi-tier distributed storage in LHD

International Nuclear Information System (INIS)

Nakanishi, Hideya; Masaki, Ohsuna; Mamoru, Kojima; Setsuo, Imazu; Miki, Nonomura; Kenji, Watanabe; Masayoshi, Moriya; Yoshio, Nagayama; Kazuo, Kawahata

2008-01-01

Recent 'data explosion' induces the demand for high flexibility of storage extension and data migration. The data amount of LHD plasma diagnostics has grown 4.6 times bigger than that of three years before. Frequent migration or replication between plenty of distributed storage becomes mandatory, and thus increases the human operational costs. To reduce them computationally, a new adaptive migration scheme has been developed on LHD's multi-tier distributed storage. So-called the HSM (Hierarchical Storage Management) software usually adopts a low-level cache mechanism or simple watermarks for triggering the data stage-in and out between two storage devices. However, the new scheme can deal with a number of distributed storage by the facilitator database that manages the whole data locations with their access histories and retrieval priorities. Not only the inter-tier migration but also the intra-tier replication and moving are even manageable so that it can be a big help in extending or replacing storage equipment. The access history of each data object is also utilized to optimize the volume size of fast and costly RAID, in addition to a normal cache effect for frequently retrieved data. The new scheme has been verified its effectiveness so that LHD multi-tier distributed storage and other next-generation experiments can obtain such the flexible expandability

High-energy tritium beams as current drivers in tokamak reactors

International Nuclear Information System (INIS)

Mikkelsen, D.R.; Grisham, L.R.

1983-04-01

The effect on neutral-beam design and reactor performance of using high-energy (approx. 3-10 MeV) tritium neutral beams to drive steady-state tokamak reactors is considered. The lower current of such beams leads to several advantages over lower-energy neutral beams. The major disadvantage is the reduction of the reactor output caused by the lower current-drive efficiency of the high-energy beams

Uplink Interference Analysis for Two-tier Cellular Networks with Diverse Users under Random Spatial Patterns

OpenAIRE

Bao, Wei; Liang, Ben

2013-01-01

Multi-tier architecture improves the spatial reuse of radio spectrum in cellular networks, but it introduces complicated heterogeneity in the spatial distribution of transmitters, which brings new challenges in interference analysis. In this work, we present a stochastic geometric model to evaluate the uplink interference in a two-tier network considering multi-type users and base stations. Each type of tier-1 users and tier-2 base stations are modeled as independent homogeneous Poisson point...

Secret high-temperature reactor concept for inertial fusion

International Nuclear Information System (INIS)

Monsler, M.J.; Meier, W.R.

1983-01-01

The goal of our SCEPTRE project was to create an advanced second-generation inertial fusion reactor that offers the potential for either of the following: (1) generating electricity at 50% efficiency, (2) providing high temperature heat (850 0 C) for hydrogen production, or (3) producing fissile fuel for light-water reactors. We have found that these applications are conceptually feasible with a reactor that is intrinsically free of the hazards of catastrophic fire or tritium release

Three Tiers of CSR

DEFF Research Database (Denmark)

Aggerholm, Helle Kryger; Trapp, Leila

2014-01-01

for understanding corporate approaches to CSR by examining how several companies position themselves thematically in CEO introductions to sustainability reports. On the basis of this, we then evaluate the practical value of this typology for assisting those who work with CSR strategy. The analysis revealed...... of the identified strengths and weaknesses of the typology, we develop a practitioner-focused, three-tiered model that can strategically guide the development of CSR programs....

Second-Tier Database for Ecosystem Focus, 2000-2001 Annual Report.

Energy Technology Data Exchange (ETDEWEB)

Van Holmes, Chris; Muongchanh, Christine; Anderson, James J. (University of Washington, School of Aquatic and Fishery Sciences, Seattle, WA)

2001-11-01

The Second-Tier Database for Ecosystem Focus (Contract 00004124) provides direct and timely public access to Columbia Basin environmental, operational, fishery and riverine data resources for federal, state, public and private entities. The Second-Tier Database known as Data Access in Realtime (DART) does not duplicate services provided by other government entities in the region. Rather, it integrates public data for effective access, consideration and application.

Cleavage-Independent HIV-1 Trimers From CHO Cell Lines Elicit Robust Autologous Tier 2 Neutralizing Antibodies

Directory of Open Access Journals (Sweden)

Shridhar Bale

2018-05-01

Full Text Available Native flexibly linked (NFL HIV-1 envelope glycoprotein (Env trimers are cleavage-independent and display a native-like, well-folded conformation that preferentially displays broadly neutralizing determinants. The NFL platform simplifies large-scale production of Env by eliminating the need to co-transfect the precursor-cleaving protease, furin that is required by the cleavage-dependent SOSIP trimers. Here, we report the development of a CHO-M cell line that expressed BG505 NFL trimers at a high level of homogeneity and yields of ~1.8 g/l. BG505 NFL trimers purified by single-step lectin-affinity chromatography displayed a native-like closed structure, efficient recognition by trimer-preferring bNAbs, no recognition by non-neutralizing CD4 binding site-directed and V3-directed antibodies, long-term stability, and proper N-glycan processing. Following negative-selection, formulation in ISCOMATRIX adjuvant and inoculation into rabbits, the trimers rapidly elicited potent autologous tier 2 neutralizing antibodies. These antibodies targeted the N-glycan “hole” naturally present on the BG505 Env proximal to residues at positions 230, 241, and 289. The BG505 NFL trimers that did not expose V3 in vitro, elicited low-to-no tier 1 virus neutralization in vivo, indicating that they remained intact during the immunization process, not exposing V3. In addition, BG505 NFL and BG505 SOSIP trimers expressed from 293F cells, when formulated in Adjuplex adjuvant, elicited equivalent BG505 tier 2 autologous neutralizing titers. These titers were lower in potency when compared to the titers elicited by CHO-M cell derived trimers. In addition, increased neutralization of tier 1 viruses was detected. Taken together, these data indicate that both adjuvant and cell-type expression can affect the elicitation of tier 2 and tier 1 neutralizing responses in vivo.

Otter trawls in Greece: Landing profiles and potential mιtiers

Directory of Open Access Journals (Sweden)

S. KATSANEVAKIS

2010-02-01

Full Text Available A fleet of 326 bottom trawlers operate in Greek Seas and their landings represent approximately 30% of the total fish production in Greece. In this study, otter trawl landings data were analyzed in order to identify potential métiers. Landings data between 2002 and 2006 were used, collected from 42 ports in the Aegean and East Ionian Sea. A three-step procedure was applied to identify potential métiers: the first step involved a factorial analysis of the log-transformed landings profiles, the second step a classification of the factorial coordinates, and the third step a further aggregation of clusters based on expert knowledge. In all, six potential métiers were identified in the Aegean Sea, and five in the Ionian Sea. The most important target species were European hake (Merluccius merluccius, deepwater pink shrimp (Parapenaeus longirostris, red mullet (Mullus barbatus, caramote prawn (Melicertus kerathurus, picarel (Spicara smaris, cephalopods, bogue (Boops boops, anglers (Lophiusspp., and Norway lobster (Nephrops norvegicus. Otter trawls in Greece use more or less the same gear with minor modification, and métier selection is basically reflected as a choice of geographical sub-area and hauling depth. The limitations of using landings profiles to identify métiers and the need for further verification are discussed.

The Evolving role of Tier2s in ATLAS with the new Computing and Data Distribution Model

CERN Document Server

Gonzalez de la Hoz, S; The ATLAS collaboration

2012-01-01

Originally the ATLAS computing model assumed that the Tier2s of each of the 10 clouds should keep on disk collectively at least one copy of all "active" AOD and DPD datasets. Evolution of ATLAS computing and data models requires changes in ATLAS Tier2s policy for the data replication, dynamic data caching and remote data access. Tier2 operations take place completely asynchronously with respect to data taking. Tier2s do simulation and user analysis. Large-scale reprocessing jobs on real data are at first taking place mostly at Tier1s but will progressively move to Tier2s as well. The availability of disk space at Tier2s is extremely important in the ATLAS computing model as it allows more data to be readily accessible for analysis jobs to all users, independently of their geographical location. The Tier2s disk space has been reserved for real, simulated, calibration and alignment, group, and user data. A buffer disk space is needed for input and output data for simulations jobs. Tier2s are going to be used mo...

The evolving role of Tier2s in ATLAS with the new Computing and Data Distribution model

CERN Document Server

Gonzalez de la Hoz, S

2012-01-01

Originally the ATLAS computing model assumed that the Tier2s of each of the 10 clouds should keep on disk collectively at least one copy of all "active" AOD and DPD datasets. Evolution of ATLAS computing and data models requires changes in ATLAS Tier2s policy for the data replication, dynamic data caching and remote data access. Tier2 operations take place completely asynchronously with respect to data taking. Tier2s do simulation and user analysis. Large-scale reprocessing jobs on real data are at first taking place mostly at Tier1s but will progressively move to Tier2s as well. The availability of disk space at Tier2s is extremely important in the ATLAS computing model as it allows more data to be readily accessible for analysis jobs to all users, independently of their geographical location. The Tier2s disk space has been reserved for real, simulated, calibration and alignment, group, and user data. A buffer disk space is needed for input and output data for simulations jobs. Tier2s are going to be used mo...

High Flux Isotope Reactor technical specifications

International Nuclear Information System (INIS)

1985-11-01

This report gives technical specifications for the High Flux Isotope Reactor (HFIR) on the following: safety limits and limiting safety system settings; limiting conditions for operation; surveillance requirements; design features; and administrative controls

Calcium oxide/carbon dioxide reactivity in a packed bed reactor of a chemical heat pump for high-temperature gas reactors

International Nuclear Information System (INIS)

Kato, Yukitaka; Yamada, Mitsuteru; Kanie, Toshihiro; Yoshizawa, Yoshio

2001-01-01

The thermal performance of a chemical heat pump that uses a calcium oxide/carbon dioxide reaction system was discussed as a heat storage system for utilizing heat output from high temperature gas reactors (HTGR). Calcium oxide/carbon dioxide reactivity for the heat pump was measured using a packed bed reactor containing 1.0 kg of reactant. The reactor was capable of storing heat at 900 deg. C by decarbonation of calcium carbonate and generating up to 997 deg. C by carbonation of calcium oxide. The amount of stored heat in the reactor was 800-900 kJ kg -1 . The output temperature of the reactor could be controlled by regulating the carbonation pressure. The thermal storage performance of the reactor was superior to that of conventional sensible heat storage systems. A heat pump using this CaO/CO 2 reactor is expected to contribute to thermal load leveling and to realize highly efficient utilization of HTGR output due to the high heat storage density and high-quality temperature output of the heat pump

Knowledge Management Systems and Open Innovation in Second Tier UK Universities

Science.gov (United States)

Chaston, Ian

2012-01-01

The purpose of this paper is to examine the performance of second tier UK universities in relation to the effectiveness of their knowledge management systems and involvement in open innovation. Data were acquired using a mail survey of academic staff in social science and business faculties in second tier institutions. The results indicate that…

A Step-by-Step Guide to Tier 2 Behavioral Progress Monitoring

Science.gov (United States)

Bruhn, Allison L.; McDaniel, Sara C.; Rila, Ashley; Estrapala, Sara

2018-01-01

Students who are at risk for or show low-intensity behavioral problems may need targeted, Tier 2 interventions. Often, Tier 2 problem-solving teams are charged with monitoring student responsiveness to intervention. This process may be difficult for those who are not trained in data collection and analysis procedures. To aid practitioners in these…

Thermal Energetic Reactor with High Reproduction of Fission Materials

Directory of Open Access Journals (Sweden)

Vladimir M. Kotov

2012-01-01

On the base of thermal reactors with high fission materials reproduction world atomic power engineering development supplying higher power and requiring smaller speed of raw uranium mining, than in the variant with fast reactors, is possible.

Annual report 1990. Operation of the high flux reactor

International Nuclear Information System (INIS)

Ahlf, J.; Gevers, A.

1990-01-01

In 1990 the operation of the High Flux Reactor was carried out as planned. The availability was 96% of scheduled operating time. The average utilization of the reactor was 71% of the practical limit. The reactor was utilized for research programmes in support of nuclear fission reactors and thermonuclear fusion, for fundamental research with neutrons, for radioisotope production, and for various smaller activities. General activities in support of running irradiation programmes progressed in the normal way. Development activities addressed upgrading of irradiation devices, neutron radiography and neutron capture therapy

Annual report 1989 operation of the high flux reactor

International Nuclear Information System (INIS)

Ahlf, J.; Gevers, A.

1989-01-01

In 1989 the operation of the High Flux Reactor Petten was carried out as planned. The availability was more than 100% of scheduled operating time. The average occupation of the reactor by experimental devices was 72% of the practical occupation limit. The reactor was utilized for research programmes in support of nuclear fission reactors and thermonuclear fusion, for fundamental research with neutrons and for radioisotope production. General activities in support of running irradiation programmes progressed in the normal way. Development activities addressed upgrading of irradiation devices, neutron radiography and neutron capture therapy

Hydrogen production from high temperature electrolysis and fusion reactor

International Nuclear Information System (INIS)

Dang, V.D.; Steinberg, J.F.; Issacs, H.S.; Lazareth, O.; Powell, J.R.; Salzano, F.J.

1978-01-01

Production of hydrogen from high temperature electrolysis of steam coupled with a fusion reactor is studied. The process includes three major components: the fusion reactor, the high temperature electrolyzer and the power conversion cycle each of which is discussed in the paper. Detailed process design and analysis of the system is examined. A parametric study on the effect of process efficiency is presented

Assessing the nutritional quality of diets of Canadian children and adolescents using the 2014 Health Canada Surveillance Tool Tier System.

Science.gov (United States)

Jessri, Mahsa; Nishi, Stephanie K; L'Abbe, Mary R

2016-05-10

Health Canada's Surveillance Tool (HCST) Tier System was developed in 2014 with the aim of assessing the adherence of dietary intakes with Eating Well with Canada's Food Guide (EWCFG). HCST uses a Tier system to categorize all foods into one of four Tiers based on thresholds for total fat, saturated fat, sodium, and sugar, with Tier 4 reflecting the unhealthiest and Tier 1 the healthiest foods. This study presents the first application of the HCST to examine (i) the dietary patterns of Canadian children, and (ii) the applicability and relevance of HCST as a measure of diet quality. Data were from the nationally-representative, cross-sectional Canadian Community Health Survey 2.2. A total of 13,749 participants aged 2-18 years who had complete lifestyle and 24-hour dietary recall data were examined. Dietary patterns of Canadian children and adolescents demonstrated a high prevalence of Tier 4 foods within the sub-groups of processed meats and potatoes. On average, 23-31 % of daily calories were derived from "other" foods and beverages not recommended in EWCFG. However, the majority of food choices fell within the Tier 2 and 3 classifications due to lenient criteria used by the HCST for classifying foods. Adherence to the recommendations presented in the HCST was associated with closer compliance to meeting nutrient Dietary Reference Intake recommendations, however it did not relate to reduced obesity as assessed by body mass index (p > 0.05). EWCFG recommendations are currently not being met by most children and adolescents. Future nutrient profiling systems need to incorporate both positive and negative nutrients and an overall score. In addition, a wider range of nutrient thresholds should be considered for HCST to better capture product differences, prevent categorization of most foods as Tiers 2-3 and provide incentives for product reformulation.

Gas reactor and associated nuclear experience in the UK relevant to high temperature reactor engineering

International Nuclear Information System (INIS)

Beech, D.J.; May, R.

2000-01-01

In the UK, the NNC played a leading role in the design and build of all of the UK's commercial magnox reactors and advanced gas-cooled reactors (AGRs). It was also involved in the DRAGON project and was responsible for producing designs for large scale HTRs and other gas reactor designs employing helium and carbon dioxide coolants. This paper addresses the gas reactor experience and its relevance to the current HTR designs under development which use helium as the coolant, through the consideration of a representative sample of the issues addressed in the UK by the NNC in support of the AGR and other reactor programmes. Modern HTR designs provide unique engineering challenges. The success of the AGR design, reflected in the extended lifetimes agreed upon by the licensing authorities at many stations, indicates that these challenges can be successfully overcome. The UK experience is unique and provides substantial support to future gas reactor and high temperature engineering studies. (authors)

Design of high temperature Engineering Test Reactor (HTTR)

International Nuclear Information System (INIS)

Saito, Shinzo; Tanaka, Toshiyuki; Sudo, Yukio

1994-09-01

Construction of High Temperature Engineering Test Reactor (HTTR) is now underway to establish and upgrade basic technologies for HTGRs and to conduct innovative basic research at high temperatures. The HTTR is a graphite-moderated and helium gas-cooled reactor with 30 MW in thermal output and outlet coolant temperature of 850degC for rated operation and 950degC for high temperature test operation. It is planned to conduct various irradiation tests for fuels and materials, safety demonstration tests and nuclear heat application tests. JAERI received construction permit of HTTR reactor facility in February 1990 after 22 months of safety review. This report summarizes evaluation of nuclear and thermal-hydraulic characteristics, design outline of major systems and components, and also includes relating R and D result and safety evaluation. Criteria for judgment, selection of postulated events, major analytical conditions for anticipated operational occurrences and accidents, computer codes used in safety analysis and evaluation of each event are presented in the safety evaluation. (author)

Multi-tiered sports arbitrations in the Republic of Serbia

Directory of Open Access Journals (Sweden)

Galantić Miloš B.

2015-01-01

Full Text Available Contrary to popular perception of the legal profession, multi-tier arbitrations are neither new, nor uncommon phenomenon. With growing need of the community to arbitration becomes real, not just theoretical, alternative to judicial resolution of disputes, arbitration accepts more judicial characteristics, among which is one of the most important and at the same time controversial - multi-tiered dispute resolution. Multi-tiered arbitration proceeding is traditionally present in commercial and investment arbitrations. However, in recent decades, significant international arbitration institutions introduced the option for consensual review of arbitration awards. Sports law is an area where, by the end of the twentieth century, the phenomenon was unnoticed present. The international sports community, as a precondition for the survival of autonomous settlement of disputes, choose dispute settlement by arbitration, but with a number of significant modifications. One of the most specific is multi-tiered arbitration, especially regarding the most important cases. The main reason for such behaviour is the aspiration of the international sports community, following the example of national courts, to organize efficient, quality and final way of resolving disputes within its jurisdiction. Permanent Court of arbitration of the Olympic Committee of Serbia follows the mentioned logic, thanks to the provisions of the Sports Act and contrary to the Arbitration act, and introduces the possibility of reviewing its decision in front of the Court of arbitration for sport based in Lausanne.

State of development of high temperature gas-cooled reactors in foreign countries

International Nuclear Information System (INIS)

Sudo, Yukio

1990-01-01

Emphasis has been placed in the development of high temperature gas-cooled reactors on high thermal efficiency as power reactors and the reactor from which nuclear heat can be utilized. In U.K., as the international project 'Dragon Project', the experimental Dragon reactor for research use with 20 MWt output and exit coolant temperature 750 deg C was constructed, and operated till 1976. Coated fuel particles were developed. In West Germany, the experimental power reactor AVR with 46 MWt and 15 MWe output was operated till 1988. The prototype power reactor THTR-300 with 300 MWe output and 750 deg C exit temperature is in commercial operation. In USA, the experimental power reactor Peach Bottom reactor with 40 MWe output and 728 deg C exit temperature was operated till 1974. The prototype Fort Saint Vrain power reactor with 330 MWe output and 782 deg C exit temperature was operated till 1989. In USSR, the modular VGM with 200 MWh output is at the planning stage. Also in China, high temperature gas-cooled reactors are at the design stage. Switzerland has taken part in various international projects. (K.I.)

Retrospective on the Seniors' Council Tier 1 LDRD portfolio.

Energy Technology Data Exchange (ETDEWEB)

Ballard, William Parker

2012-04-01

This report describes the Tier 1 LDRD portfolio, administered by the Seniors Council between 2003 and 2011. 73 projects were sponsored over the 9 years of the portfolio at a cost of $10.5 million which includes $1.9M of a special effort in directed innovation targeted at climate change and cyber security. Two of these Tier 1 efforts were the seeds for the Grand Challenge LDRDs in Quantum Computing and Next Generation Photovoltaic conversion. A few LDRDs were terminated early when it appeared clear that the research was not going to succeed. A great many more were successful and led to full Tier 2 LDRDs or direct customer sponsorship. Over a dozen patents are in various stages of prosecution from this work, and one project is being submitted for an R and D 100 award.

Changes of ticagrelor formulary tiers in the USA: targeting private insurance providers away from government-funded plans.

Science.gov (United States)

Serebruany, Victor L; Dinicolantonio, James J

2013-01-01

Ticagrelor (Brilinta®) is a new oral reversible antiplatelet agent approved by the FDA in July 2011 based on the results of the PLATO (Platelet Inhibition and Patient Outcomes) trial. However, despite very favorable and broad indications, the current clinical utilization of ticagrelor is woefully small. We aimed to compare ticagrelor formulary tiers for major private (n = 8) and government-funded (n = 4) insurance providers for 2012-2013. Over the last year, ticagrelor placement improved, becoming a preferred drug (from Tier 3 in 2012 to Tier 2 in 2013) for Medco, moving from Tier 4 (with a prior approval requirement) to Tier 3 (no prior approval) for the United Health Care Private Plan and achieving Tier 3 status for Apex in 2013. In contrast, ticagrelor placement did not improve for New York Medicaid, retaining Tier 3 status. In addition, many Medicare Part D formularies have significantly worse coverage than most private plans. For example, Humana Medicare Part D has Tier 3 status requiring step therapy and quantity limits, SilverScript (CVS Caremark) Part D is Tier 3 and the American Association of Retired Persons (United Health Care) Medicare Part D is Tier 4 requiring prior approval. Ticagrelor formulary placement is significantly better for most private providers than for government-funded plans, which may possibly be due to the selective targeting of private insurance providers and the simultaneous avoidance of government-funded plans. © 2013 S. Karger AG, Basel.

Results of Laboratory Testing of 15 Cookstove Designs in Accordance with the ISO/IWA Tiers of Performance.

Science.gov (United States)

Still, Dean; Bentson, Samuel; Li, Haixi

2015-03-01

The widespread adoption and sustained use of modern cookstoves has the potential to reduce harmful effects to climate, health, and the well-being of approximately one-third of the world's population that currently rely on biomass fuel for cooking and heating. In an effort to understand and develop cleaner burning and more efficient cookstoves, 15 stove design and fuel/loading combinations were evaluated in the laboratory using the International Workshop Agreement's five-tiered (0-4) rating system for fuel use and emissions. The designs evaluated include rocket-type combustion chamber models including reduced firepower, sunken pots, and chimneys (three stoves); gasifier-type combustion chambers using prepared fuels in the form of wood pellets (four stoves); forced draft stoves with a small electric fan (five stoves); and a single insulated charcoal stove with preheated secondary air. It was found that a charcoal burning stove was the only stove to meet all the Tier 4 levels of performance. Achieving over 40% thermal efficiency at high power was made possible by reducing firepower and gaps around the pot, although batch-fed stoves generally do not "turn down" for optimal low power performance. While all stoves met Tier 4 for carbon monoxide, only stoves equipped with electrical fans reduced respirable particulate matter to Tier 4 levels. Finally, stoves with chimneys and integrated pots were fuel efficient and virtually eliminated indoor emissions. It is hoped that these design techniques will be useful in further development and evolution of high-performance cookstove designs.

Summary - Advanced high-temperature reactor for hydrogen and electricity production

International Nuclear Information System (INIS)

Forsberg, Charles W.

2001-01-01

Historically, the production of electricity has been assumed to be the primary application of nuclear energy. That may change. The production of hydrogen (H 2 ) may become a significant application. The technology to produce H 2 using nuclear energy imposes different requirements on the reactor, which, in turn, may require development of new types of reactors. Advanced High Temperature reactors can meet the high temperature requirements to achieve this goal. This alternative application of nuclear energy may necessitate changes in the regulatory structure

High performance light water reactor

International Nuclear Information System (INIS)

Squarer, D.; Schulenberg, T.; Struwe, D.; Oka, Y.; Bittermann, D.; Aksan, N.; Maraczy, C.; Kyrki-Rajamaeki, R.; Souyri, A.; Dumaz, P.

2003-01-01

The objective of the high performance light water reactor (HPLWR) project is to assess the merit and economic feasibility of a high efficiency LWR operating at thermodynamically supercritical regime. An efficiency of approximately 44% is expected. To accomplish this objective, a highly qualified team of European research institutes and industrial partners together with the University of Tokyo is assessing the major issues pertaining to a new reactor concept, under the co-sponsorship of the European Commission. The assessment has emphasized the recent advancement achieved in this area by Japan. Additionally, it accounts for advanced European reactor design requirements, recent improvements, practical design aspects, availability of plant components and the availability of high temperature materials. The final objective of this project is to reach a conclusion on the potential of the HPLWR to help sustain the nuclear option, by supplying competitively priced electricity, as well as to continue the nuclear competence in LWR technology. The following is a brief summary of the main project achievements:-A state-of-the-art review of supercritical water-cooled reactors has been performed for the HPLWR project.-Extensive studies have been performed in the last 10 years by the University of Tokyo. Therefore, a 'reference design', developed by the University of Tokyo, was selected in order to assess the available technological tools (i.e. computer codes, analyses, advanced materials, water chemistry, etc.). Design data and results of the analysis were supplied by the University of Tokyo. A benchmark problem, based on the 'reference design' was defined for neutronics calculations and several partners of the HPLWR project carried out independent analyses. The results of these analyses, which in addition help to 'calibrate' the codes, have guided the assessment of the core and the design of an improved HPLWR fuel assembly. Preliminary selection was made for the HPLWR scale

Statistics of the uplink co-tier interference in closed access heterogeneous networks

KAUST Repository

Tabassum, Hina

2013-09-01

In this paper, we derive a statistical model of the co-tier interference in closed access two tier heterogeneous wireless cellular networks with femtocell deployments. The derived model captures the impact of bounded path loss model, wall penetration loss, user distributions, random locations, and density of the femtocells. Firstly, we derive the analytical expressions for the probability density function (PDF) and moment generating function (MGF) of the co-tier interference considering a single femtocell interferer by exploiting the random disc line picking theory from geometric probability. We then derive the MGF of the cumulative interference from all femtocell interferers considering full spectral reuse in each femtocell. Orthogonal spectrum partitioning is assumed between the macrocell and femtocell networks to avoid any cross-tier interference. Finally, the accuracy of the derived expressions is validated through Monte-Carlo simulations and the expressions are shown to be useful in quantifying important network performance metrics such as ergodic capacity. © 2013 IEEE.

Creep behavior of materials for high-temperature reactor application

International Nuclear Information System (INIS)

Schneider, K.; Hartnagel, W.; Iischner, B.; Schepp, P.

1984-01-01

Materials for high-temperature gas-cooled reactor (HTGR) application are selected according to their creep behavior. For two alloys--Incoloy-800 used for the live steam tubing of the thorium high-temperature reactor and Inconel-617 evaluated for tubings in advanced HTGRs--creep curves are measured and described by equations. A microstructural interpretation is given. An essential result is that nonstable microstructures determine the creep behavior

Concept of the new generation high safety liquid metal reactor (LMFR)

International Nuclear Information System (INIS)

Alekseev, P.N.; Zverkov, Y.A.; Morozov, A.G.; Orlov, V.V.; Ponomarev-Stepnoi, N.N.; Proshkin, A.A.; Slesarev, I.S.; Subbotin, S.A.

1988-01-01

The comparative analysis of the inner stability of the liquid metal reactors to severe accidents was made using the asymptotic reactivity balance. The group of the BN-reactors, Superphenix, IFR, LMFR were considered. This paper lists the characteristics of the reactors, used in the self-protectiveness analysis. The authors present the maximum coolant temperatures in post-accident asymptotic state for IFRs as on of the possible designs of a high safety fast reactor with metal fuel, U-Pu-Zr and LMFR. As is known, these values are very important for assessment of the ATWS accidence consequences. The authors consider the following situations and their combinations: loss of reactor coolant flow-LOFWS, loss of heat sink-LOHSWS, uncontrolled reactor sodium overcooling (down to the freezing point)-OVCWS, uncontrolled excess reactivity insertion-TOPWS. The calculation results demonstrate a high stability of the IFR and LMFR reactors to the most severe accidence sequences

40 CFR 79.54 - Tier 3.

Science.gov (United States)

2010-07-01

...) Historical and/or projected production volumes and market distributions; and (iv) Estimated population and/or... areas of concern. (f) General and Pulmonary Toxicity Testing. (1) A potential need for Tier 3 general and/or pulmonary toxicity testing may be indicated if, in comparison with appropriate controls, the...

Core design concepts for high performance light water reactors

International Nuclear Information System (INIS)

Schulenberg, T.; Starflinger, J.

2007-01-01

Light water reactors operated under supercritical pressure conditions have been selected as one of the promising future reactor concepts to be studied by the Generation IV International Forum. Whereas the steam cycle of such reactors can be derived from modern fossil fired power plants, the reactor itself, and in particular the reactor core, still need to be developed. Different core design concepts shall be described here to outline the strategy. A first option for near future applications is a pressurized water reactor with 380 .deg. C core exit temperature, having a closed primary loop and achieving 2% pts. higher net efficiency and 24% higher specific turbine power than latest pressurized water reactors. More efficiency and turbine power can be gained from core exit temperatures around 500 .deg. C, which require a multi step heat up process in the core with intermediate coolant mixing, achieving up to 44% net efficiency. The paper summarizes different core and assembly design approaches which have been studied recently for such High Performance Light Water Reactors

Annual Report 1991. Operation of the high flux reactor

International Nuclear Information System (INIS)

Ahlf, J.; Gevers, A.

1992-01-01

In 1991 the operation of the High Flux Reactor was carried out as planned. The availability was more than 100% of scheduled operating time. The average utilization of the reactor was 69% of the practical limit. The reactor was utilized for research programmes in support of nuclear fission reactors and thermonuclear fusion, for fundamental research with neutrons, for radioisotope production, and for various smaller activities. Development activities addressed upgrading of irradiation devices, neutron capture therapy, neutron radiography and neutron transmutation doping of silicon. General activities in support of running irradiation programmes progressed in the normal way

The United States fluoride-salt-cooled high-temperature reactor program

International Nuclear Information System (INIS)

Holcomb, David E.

2013-01-01

The United States is pursuing the development of fluoride-salt-cooled high-temperature reactors (FHRs) through the Department of Energy's Office of Nuclear Energy (DOE-NE). FHRs, by definition, feature low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. FHRs, in principle, have the potential to economically generate large amounts of electricity while maintaining full passive safety. FHRs, however, remain a longer-term power production option. A principal development focus is, thus, on shortening, to the extent possible, the overall development time by focusing initial efforts on the longest lead-time issues. While FHRs represent a distinct reactor class, they inherit desirable attributes from other thermal power plants whose characteristics can be studied to provide general guidance on plant configuration, anticipated performance, and costs. Molten salt reactors provide experience on the materials, procedures, and components necessary to use liquid fluoride salts. Liquid-metal reactors provide design experience on using low-pressure liquid coolants, passive decay heat removal, and hot refueling. High-temperature gas-cooled reactors provide experience with coated-particle fuel and graphite components. Light-water reactors show the potential of transparent, high-heat-capacity coolants with low chemical reactivity. The FHR development efforts include both reactor concept and technology developments and are being broadly pursued. Oak Ridge National Laboratory (ORNL) provides technical leadership to the effort and is performing concept development on both a large base-load-type FHR as well as a small modular reactor (SMR) in addition to performing a broad scope of technology developments. Idaho National Laboratory (INL) is providing coated-particle fuel irradiation testing as well as developing high-temperature steam generator technology. The Massachusetts Institute of Technology (MIT

Design activity of IHI on the experimental multipurpose high temperature gas-cooled reactor

International Nuclear Information System (INIS)

1978-01-01

With conspicuous interest and attention paid by iron and steel manufacturing industries, the development of the multipurpose high temperature gas-cooled reactor, namely the process heat reactor has been energetically discussed in Japan. The experimental multipurpose high temperature gas-cooled reactor, planned by JAERI (the Japan Atomic Energy Research Institute), is now at the end of the adjustment design stage and about to enter the system synthesizing design stage. The design of the JAERI reactor as a pilot plant for process heat reactors that make possible the direct use of the heat, produced in the reactor, for other industrial uses was started in 1969, and has undergone several revisions up to now. The criticality of the JAERI reactor is expected to be realized before 1985 according to the presently published program. IHI has engaged in the developing work of HTGR (high temperature gas-cooled reactor) including VHTR (very high temperature gas-cooled reactor) for over seven years, producing several achievements. IHI has also participated in the JAERI project since 1973 with some other companies concerned in this field. The design activity of IHI in the development of the JAERI reactor is briefly presented in this paper. (auth.)

Search-based Tier Assignment for Optimising Offline Availability in Multi-tier Web Applications

OpenAIRE

Philips, Laure; De Koster, Joeri; De Meuter, Wolfgang; De Roover, Coen

2017-01-01

Web programmers are often faced with several challenges in the development process of modern, rich internet applications. Technologies for the different tiers of the application have to be selected: a server-side language, a combination of JavaScript, HTML and CSS for the client, and a database technology. Meeting the expectations of contemporary web applications requires even more effort from the developer: many state of the art libraries must be mastered and glued together. This leads to an...

Development of two tier test to assess conceptual understanding in heat and temperature

Science.gov (United States)

Winarti; Cari; Suparmi; Sunarno, Widha; Istiyono, Edi

2017-01-01

Heat and temperature is a concept that has been learnt from primary school to undergraduate levels. One problem about heat and temperature is that they are presented abstractly, theoretical concept. A student conceptual frameworks develop from their daily experiences. The purpose of this research was to develop a two-tier test of heat and temperature concept and measure conceptual understanding of heat and temperature of the student. This study consist of two method is qualitative and quantitative method. The two-tier test was developed using procedures defined by Borg and Gall. The two-tier test consisted of 20 question and was tested for 137 students for collecting data. The result of the study showed that the two-tier test was effective in determining the students’ conceptual understanding and also it might be used as an alternative for assessment and evaluation of students’ achievement

Instrumentation for the advanced high-flux reactor workshop: proceedings

International Nuclear Information System (INIS)

Moon, R.M.

1984-01-01

The purpose of the Workshop on Instrumentation for the Advanced High-Flux Reactor, held on May 30, 1984, at the Oak Ridge National Laborattory, was two-fold: to announce to the scientific community that ORNL has begun a serious effort to design and construct the world's best research reactor, and to solicit help from the scientific community in planning the experimental facilities for this reactor. There were 93 participants at the workshop. We are grateful to the visiting scientists for their enthusiasm and interest in the reactor project. Our goal is to produce a reactor with a peak thermal flux in a large D 2 O reflector of 5 x 10 15 n/cm 2 s. This would allow the installation of unsurpassed facilities for neutron beam research. At the same time, the design will provide facilities for isotope production and materials irradiation which are significantly improved over those now available at ORNL. This workshop focussed on neutron beam facilities; the input from the isotope and materials irradiation communities will be solicited separately. The reactor project enjoys the full support of ORNL management; the present activities are financed by a grant of $663,000 from the Director's R and D Fund. However, we realize that the success of the project, both in realization and in use of the reactor, depends on the support and imagination of a broad segment of the scientific community. This is more a national project than an ORNL project. The reactor would be operated as a national user facility, open to any research proposal with high scientific merit. It is therefore important that we maintain a continuing dialogue with outside scientists who will be the eventual users of the reactor and the neutron beam facilities. The workshop was the first step in establishing this dialogue; we anticipate further workshops as the project continues

Transmutation of technetium into stable ruthenium in high flux conceptual research reactor

International Nuclear Information System (INIS)

Amrani, N.; Boucenna, A.

2007-01-01

The effectiveness of transmutation for the long lived fission product technetium-99 in high flux research reactor, considering its large capture cross section in thermal and epithermal region is evaluated. The calculation of Ruthenium concentration evolution under irradiation was performed using Chain Solver 2.20 code. The approximation used for the transmutation calculation is the assumption that the influence of change in irradiated materials structures on the reactor operator mode characteristics is insignificant. The results on Technetium transmutation in high flux research reactor suggested an effective use of this kind of research reactors. The evaluation brings a new concept of multi-recycle Technetium transmutation using HFR T RAN (High Flux Research Reactor for Transmutation)

Cross-validation and refinement of the Stoffenmanager as a first tier exposure assessment tool for REACH

NARCIS (Netherlands)

Schinkel, J.; Fransman, W.; Heussen, H.; Kromhout, H.; Marquart, H.; Tielemans, E.

2010-01-01

Objectives: For regulatory risk assessment under REACH a tiered approach is proposed in which the first tier models should provide a conservative exposure estimate that can discriminate between scenarios which are of concern and those which are not. The Stoffenmanager is mentioned as a first tier

Cross-validation and refinement of the Stoffenmanager as a first tier exposure assessment tool for REACH.

NARCIS (Netherlands)

Schinkel, J.; Fransman, W.; Heussen, H.; Kromhout, H.; Marquart, H.; Tielemans, E.

2010-01-01

OBJECTIVES: For regulatory risk assessment under REACH a tiered approach is proposed in which the first tier models should provide a conservative exposure estimate that can discriminate between scenarios which are of concern and those which are not. The Stoffenmanager is mentioned as a first tier

Effect of cage tier and age on performance, egg quality and stress ...

African Journals Online (AJOL)

This study was conducted to investigate the effects of cage tier and age on performance characteristics of layer hybrids, egg quality and some stress parameters. Ninety laying hens (hybrid ATAK-S) of similar bodyweights were used in the experiment. They were housed in three-tier conventional battery cages (bottom, ...

Advanced High Temperature Reactor Systems and Economic Analysis

Energy Technology Data Exchange (ETDEWEB)

Holcomb, David Eugene [ORNL; Peretz, Fred J [ORNL; Qualls, A L [ORNL

2011-09-01

The Advanced High Temperature Reactor (AHTR) is a design concept for a large-output [3400 MW(t)] fluoride-salt-cooled high-temperature reactor (FHR). FHRs, by definition, feature low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. The AHTR's large thermal output enables direct comparison of its performance and requirements with other high output reactor concepts. As high-temperature plants, FHRs can support either high-efficiency electricity generation or industrial process heat production. The AHTR analysis presented in this report is limited to the electricity generation mission. FHRs, in principle, have the potential to be low-cost electricity producers while maintaining full passive safety. However, no FHR has been built, and no FHR design has reached the stage of maturity where realistic economic analysis can be performed. The system design effort described in this report represents early steps along the design path toward being able to predict the cost and performance characteristics of the AHTR as well as toward being able to identify the technology developments necessary to build an FHR power plant. While FHRs represent a distinct reactor class, they inherit desirable attributes from other thermal power plants whose characteristics can be studied to provide general guidance on plant configuration, anticipated performance, and costs. Molten salt reactors provide experience on the materials, procedures, and components necessary to use liquid fluoride salts. Liquid metal reactors provide design experience on using low-pressure liquid coolants, passive decay heat removal, and hot refueling. High temperature gas-cooled reactors provide experience with coated particle fuel and graphite components. Light water reactors (LWRs) show the potentials of transparent, high-heat capacity coolants with low chemical reactivity. Modern coal-fired power plants provide design experience

Very-high-temperature reactors for future use

International Nuclear Information System (INIS)

Kasten, P.R.

1988-01-01

Very-High-Temperature Reactors (VHTRs) show promise for economic generation of electricity and of high-temperature process heat. The key is the development of high-temperature materials which permit gas turbine VHTRs to generate electricity economically, at helium temperatures which can be used for fossil fuel conversion processes. 7 refs., 5 figs

The primary circuit of the dragon high temperature reactor experiment

International Nuclear Information System (INIS)

Simon, R.

2005-01-01

The 20 MWth Dragon Reactor Experiment was the first HTGR (High Temperature Gas-cooled Reactor) with coated particle fuel. Its purpose was to test fuel and materials for the High Temperature Reactor programmes pursued in Europe 40 years ago. This paper describes the design and construction of the primary (helium) circuit. It summarizes the main design objectives, lists the performance data and explains the flow paths of the heat removal and helium purification systems. The principal circuit accidents postulated are discussed and the choice of the main construction materials is given. (author)

Assessment of very high-temperature reactors in process application. Appendix I. Evaluation of the reactor system

International Nuclear Information System (INIS)

Jones, J.E. Jr.; Spiewak, I.

1976-12-01

In April 1974, the U.S. Atomic Energy Commission [now the Energy Research and Development Administration (ERDA)] authorized General Atomic Company, General Electric Company, and Westinghouse Electric Corp., Astronuclear Laboratory, to assess the available technology for producing heat using very high-temperature nuclear reactors. An evaulation of these studies and of the technical and economic potential of very high-temperature reactors (VHTR) is presented. The VHTR is a helium-cooled graphite-moderated reactor. The concepts and technology are evaluated for producing process stream temperatures of 649, 760, 871, 982, and 1093 0 C (1200, 1400, 1600, 1800, and 2000 0 F). There are a number of large industrial process heat applications that could utilize the VHTR

Evaluation of strategies for end storage of high-level reactor fuel

International Nuclear Information System (INIS)

2001-01-01

This report evaluates a national strategy for end-storage of used high-level reactor fuel from the research reactors at Kjeller and in Halden. This strategy presupposes that all the important phases in handling the high-level material, including temporary storage and deposition, are covered. The quantity of spent fuel from Norwegian reactors is quite small. In addition to the technological issues, ethical, environmental, safety and economical requirements are emphasized

The dual fluid reactor - a new concept for a highly effective fast reactor

Energy Technology Data Exchange (ETDEWEB)

Huke, A.; Ruprecht, G. [Institut fur Festkorper-Kernphysik gGmbH, Leistikowstr, Berlin (Germany); WeiBbach, D. [Institut fur Festkorper-Kernphysik gGmbH, Leistikowstr, Berlin (Germany); Univ. Szczecin, ul. Wielkopolska, Inst. Fizyki, Wydzial Matematyczno-Fizyczny, Szczecin, (Poland); Gottlieb, S. [Institut fur Festkorper-Kernphysik gGmbH, Leistikowstr, Berlin (Germany); Hussein, A. [Institut fur Festkorper-Kernphysik gGmbH, Leistikowstr, Berlin (Germany); Univ. of Northern British Columbia, Dept. of Physics, Prince George, BC (Canada); Czerski, K. [Institut fur Festkorper-Kernphysik gGmbH, Leistikowstr, Berlin (Germany); Univ. Szczecin, ul. Wielkopolska, Inst. Fizyki, Wydzial Matematyczno-Fizyczny, Szczecin, (Poland)

2014-07-01

The Dual Fluid Reactor, DFR, is a novel concept of a fast heterogeneous nuclear reactor. Its key feature is the employment of two separate liquid cycles, one for fuel and one for the coolant. As opposed to other liquid-fuel concepts like the molten-salt fast reactor (MSFR), in the DFR both cycles can be separately optimized for their respective purpose, leading to advantageous consequences: A very high power density resulting in enormous cost savings, and a highly negative temperature feedback coefficient, enabling a self-regulation without any control rods or mechanical parts in the core. The fuel liquid, an undiluted actinide trichloride (consisting of isotope-purified {sup 37}Cl) in the reference design, circulates at an operating temperature of 1300 K and can be processed on-line in a small internal processing unit utilizing fractionated distillation or electro refining. Medical radioisotopes like Mo-99/Tc-99m are by-products and can be provided right away. In a more advanced design, an actinide metal alloy melt with an appropriately low solidus temperature is well possible which further compactifies the core and allows to further increase the operating temperature due to its high heat conductivity. The best choice for the coolant is pure lead which yields a very hard neutron spectrum. (author)

ATLAS off-Grid sites (Tier 3) monitoring. From local fabric monitoring to global overview of the VO computing activities

CERN Document Server

PETROSYAN, A; The ATLAS collaboration; BELOV, S; ANDREEVA, J; KADOCHNIKOV, I

2012-01-01

The ATLAS Distributed Computing activities have so far concentrated in the "central" part of the experiment computing system, namely the first 3 tiers (the CERN Tier0, 10 Tier1 centers and over 60 Tier2 sites). Many ATLAS Institutes and National Communities have deployed (or intend to) deploy Tier-3 facilities. Tier-3 centers consist of non-pledged resources, which are usually dedicated to data analysis tasks by the geographically close or local scientific groups, and which usually comprise a range of architectures without Grid middleware. Therefore a substantial part of the ATLAS monitoring tools which make use of Grid middleware, cannot be used for a large fraction of Tier3 sites. The presentation will describe the T3mon project, which aims to develop a software suite for monitoring the Tier3 sites, both from the perspective of the local site administrator and that of the ATLAS VO, thereby enabling the global view of the contribution from Tier3 sites to the ATLAS computing activities. Special attention in p...

Modeling and performance of the MHTGR [Modular High-Temperature Gas-Cooled Reactor] reactor cavity cooling system

International Nuclear Information System (INIS)

Conklin, J.C.

1990-04-01

The Reactor Cavity Cooling System (RCCS) of the Modular High- Temperature Gas-Cooled Reactor (MHTGR) proposed by the U.S. Department of Energy is designed to remove the nuclear afterheat passively in the event that neither the heat transport system nor the shutdown cooling circulator subsystem is available. A computer dynamic simulation for the physical and mathematical modeling of and RCCS is described here. Two conclusions can be made form computations performed under the assumption of a uniform reactor vessel temperature. First, the heat transferred across the annulus from the reactor vessel and then to ambient conditions is very dependent on the surface emissivities of the reactor vessel and RCCS panels. These emissivities should be periodically checked to ensure the safety function of the RCCS. Second, the heat transfer from the reactor vessel is reduced by a maximum of 10% by the presence of steam at 1 atm in the reactor cavity annulus for an assumed constant in the transmission of radiant energy across the annulus can be expected to result in an increase in the reactor vessel temperature for the MHTGR. Further investigation of participating radiation media, including small particles, in the reactor cavity annulus is warranted. 26 refs., 7 figs., 1 tab

High-Temperature Gas-Cooled Test Reactor Point Design

Energy Technology Data Exchange (ETDEWEB)

Sterbentz, James William [Idaho National Laboratory; Bayless, Paul David [Idaho National Laboratory; Nelson, Lee Orville [Idaho National Laboratory; Gougar, Hans David [Idaho National Laboratory; Kinsey, James Carl [Idaho National Laboratory; Strydom, Gerhard [Idaho National Laboratory; Kumar, Akansha [Idaho National Laboratory

2016-04-01

A point design has been developed for a 200 MW high-temperature gas-cooled test reactor. The point design concept uses standard prismatic blocks and 15.5% enriched UCO fuel. Reactor physics and thermal-hydraulics simulations have been performed to characterize the capabilities of the design. In addition to the technical data, overviews are provided on the technological readiness level, licensing approach and costs.

A multi-tiered architecture for content retrieval in mobile peer-to-peer networks.

Science.gov (United States)

2012-01-01

In this paper, we address content retrieval in Mobile Peer-to-Peer (P2P) Networks. We design a multi-tiered architecture for content : retrieval, where at Tier 1, we design a protocol for content similarity governed by a parameter that trades accu...

Design and safety consideration in the High-Temperature Engineering Test Reactor (HTTR)

International Nuclear Information System (INIS)

Saito, Shinzo; Tanaka, Toshiuki; Sudo, Yukio; Baba, Osamu; Shiozawa, Shusaku; Okubo, Minoru

1990-01-01

The budget for construction of the High-Temperature Engineering Test Reactor (HTTR) was recently committed by the Government in Japan. The HTTR is a test reactor with thermal output of 30 MW and reactor outlet coolant temperature of 950 deg. C at high temperature test operation. The HTTR plant uses a pin-in-block design core and will be used as an experience leading to high temperature applications. Several major important safety considerations are adopted in the design of the HTTR. These are as follows: 1) A coated particle fuel must not be failed during a normal reactor operation and an anticipated operational occurrence; 2) Two independent and diverse reactor shut-down systems are provided in order to shut down the reactor safely and reliably in any condition; 3) Back-up reactor cooling systems which are safety ones are provided in order to remove residual heat of reactor in any condition; 4) Multiple barriers and countermeasures are provided to contain fission products such as a containment, pressure gradient between the primary and secondary cooling circuit and so on, though coated particle fuels contain fission products with high reliability; 5) The functions of materials used in the primary cooling circuit are separated to be pressure-resisting and heat-resisting in order to resolve material problems and maintain high reliability. The detailed design of the HTTR was completed with extensive accumulation of material data and component tests. (author)

Design of a management information system for the Shielding Experimental Reactor ageing management

International Nuclear Information System (INIS)

He Jie; Xu Xianhong

2010-01-01

The problem of nuclear reactor ageing is a topic of increasing importance in nuclear safety recent years. Ageing management is usually implemented for reactors maintenance. In the practice, a large number of data and records need to be processed. However, there are few professional software applications that aid reactor ageing management, especially for research reactors. This paper introduces the design of a new web-based management information system (MIS), named the Shielding Experimental Reactor Ageing Management Information System (SERAMIS). It is an auxiliary means that helps to collect data, keep records, and retrieve information for a research reactor ageing management. The Java2 Enterprise Edition (J2EE) and network database techniques, such as three-tiered model, Model-View-Controller architecture, transaction-oriented operations, and JavaScript techniques, are used in the development of this system. The functionalities of the application cover periodic safety review (PSR), regulatory references, data inspection, and SSCs classification according to ageing management methodology. Data and examples are presented to demonstrate the functionalities. For future work, techniques of data mining will be employed to support decision-making.

Design of a management information system for the Shielding Experimental Reactor ageing management

Energy Technology Data Exchange (ETDEWEB)

He Jie, E-mail: hejiejoe@163.co [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Xu Xianhong [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China)

2010-01-15

The problem of nuclear reactor ageing is a topic of increasing importance in nuclear safety recent years. Ageing management is usually implemented for reactors maintenance. In the practice, a large number of data and records need to be processed. However, there are few professional software applications that aid reactor ageing management, especially for research reactors. This paper introduces the design of a new web-based management information system (MIS), named the Shielding Experimental Reactor Ageing Management Information System (SERAMIS). It is an auxiliary means that helps to collect data, keep records, and retrieve information for a research reactor ageing management. The Java2 Enterprise Edition (J2EE) and network database techniques, such as three-tiered model, Model-View-Controller architecture, transaction-oriented operations, and JavaScript techniques, are used in the development of this system. The functionalities of the application cover periodic safety review (PSR), regulatory references, data inspection, and SSCs classification according to ageing management methodology. Data and examples are presented to demonstrate the functionalities. For future work, techniques of data mining will be employed to support decision-making.

Nuclear graphite for high temperature reactors

International Nuclear Information System (INIS)

Marsden, B.J.

2001-01-01

The cores and reflectors in modern High Temperature Gas Cooled Reactors (HTRs) are constructed from graphite components. There are two main designs; the Pebble Bed design and the Prism design. In both of these designs the graphite not only acts as a moderator, but is also a major structural component that may provide channels for the fuel and coolant gas, channels for control and safety shut off devices and provide thermal and neutron shielding. In addition, graphite components may act as a heat sink or conduction path during reactor trips and transients. During reactor operation, many of the graphite component physical properties are significantly changed by irradiation. These changes lead to the generation of significant internal shrinkage stresses and thermal shut down stresses that could lead to component failure. In addition, if the graphite is irradiated to a very high irradiation dose, irradiation swelling can lead to a rapid reduction in modulus and strength, making the component friable.The irradiation behaviour of graphite is strongly dependent on its virgin microstructure, which is determined by the manufacturing route. Nevertheless, there are available, irradiation data on many obsolete graphites of known microstructures. There is also a well-developed physical understanding of the process of irradiation damage in graphite. This paper proposes a specification for graphite suitable for modern HTRs. (author)

Development of a Three-Tier Test to Assess Misconceptions about Simple Electric Circuits

Science.gov (United States)

Pesman, Haki; Eryilmaz, Ali

2010-01-01

The authors aimed to propose a valid and reliable diagnostic instrument by developing a three-tier test on simple electric circuits. Based on findings from the interviews, open-ended questions, and the related literature, the test was developed and administered to 124 high school students. In addition to some qualitative techniques for…

New off-road engines for TIER 4 final; Neue Offroad-Motoren fuer Tier 4 final

Energy Technology Data Exchange (ETDEWEB)

Adt, Hans-Ulrich; Lehmann, Henrik [MTU Friedrichshafen GmbH, Friedrichshafen (Germany); Herter, Yvonne; Weidler, Alexander [Daimler AG, Stuttgart (Germany). Baureihe 1000

2013-03-15

To meet the off-road emission standards EU IV and EPA Tier 4 final, as of 2014 the Tognum Group will be offering newly developed engines of the Series 1000 to 1500. These MTU brand diesel engines deliver outputs ranging from 100 to 460 kW and are designed to power agricultural and forestry machinery and construction as well as special-purpose machinery. (orig.)

Wasted? Managing Decline and Marketing Difference in Third Tier Cities

Directory of Open Access Journals (Sweden)

Tara BRABAZON

2012-06-01

Full Text Available Third-tier cities are neglected in the research literature. Global and second-tier cities provide the positive, proactive applications of city imaging and creative industries strategies. However, small cities – particularly those who reached their height and notoriety through the industrial revolution – reveal few strategies for stability, let alone growth. This study investigates an unusual third-tier city: Oshawa in Ontario Canada. Known as the home of General Motors, its recent economic and social development has been tethered to the arrival of a new institution of higher education: the University of Ontario Institute of Technology. Yet this article confirms that simply opening a university is not enough to commence regeneration or renewal, particularly if an institution is imposed on unwilling residents. Therefore, an alternative strategy – involving geosocial networking – offers a way for local businesses and organizations to attract customers and provide a digital medication to analogue injustice and decay.

Optimization of the Neutronics of the Advanced High Temperature Reactor

International Nuclear Information System (INIS)

Zakova, Jitka; Talamo, Alberto

2006-01-01

In these studies, we have investigated the neutronic and safety performance of the Advanced High Temperature Reactor (AHTR) for plutonium and uranium fuels and we extended the analysis to five different coolants. The AHTR is a graphite-moderated and molten salt-cooled high temperature reactor, which takes advantage of the TRISO particles technology for the fuel utilization. The conceptual design of the core, proposed at the Oak Ridge National Laboratory, aims to provide an alternative to helium as coolant of high-temperature reactors for industrial applications like hydrogen production. We evaluated the influence of the radial reflector on the criticality of the core for the uranium and plutonium fuels and we focused on the void coefficient of 5 different molten salts; since the safety of the reactor is enhanced also by the large and negative coefficient of temperature, we completed our investigation by observing the keff changes when the graphite temperature varies from 300 to 1800 K. (authors)

A Two-Tiered Model for Analyzing Library Web Site Usage Statistics, Part 1: Web Server Logs.

Science.gov (United States)

Cohen, Laura B.

2003-01-01

Proposes a two-tiered model for analyzing web site usage statistics for academic libraries: one tier for library administrators that analyzes measures indicating library use, and a second tier for web site managers that analyzes measures aiding in server maintenance and site design. Discusses the technology of web site usage statistics, and…

Assessing the nutritional quality of diets of Canadian children and adolescents using the 2014 Health Canada Surveillance Tool Tier System

Directory of Open Access Journals (Sweden)

Mahsa Jessri

2016-05-01

Full Text Available Abstract Background Health Canada’s Surveillance Tool (HCST Tier System was developed in 2014 with the aim of assessing the adherence of dietary intakes with Eating Well with Canada’s Food Guide (EWCFG. HCST uses a Tier system to categorize all foods into one of four Tiers based on thresholds for total fat, saturated fat, sodium, and sugar, with Tier 4 reflecting the unhealthiest and Tier 1 the healthiest foods. This study presents the first application of the HCST to examine (i the dietary patterns of Canadian children, and (ii the applicability and relevance of HCST as a measure of diet quality. Methods Data were from the nationally-representative, cross-sectional Canadian Community Health Survey 2.2. A total of 13,749 participants aged 2–18 years who had complete lifestyle and 24-hour dietary recall data were examined. Results Dietary patterns of Canadian children and adolescents demonstrated a high prevalence of Tier 4 foods within the sub-groups of processed meats and potatoes. On average, 23–31 % of daily calories were derived from “other” foods and beverages not recommended in EWCFG. However, the majority of food choices fell within the Tier 2 and 3 classifications due to lenient criteria used by the HCST for classifying foods. Adherence to the recommendations presented in the HCST was associated with closer compliance to meeting nutrient Dietary Reference Intake recommendations, however it did not relate to reduced obesity as assessed by body mass index (p > 0.05. Conclusions EWCFG recommendations are currently not being met by most children and adolescents. Future nutrient profiling systems need to incorporate both positive and negative nutrients and an overall score. In addition, a wider range of nutrient thresholds should be considered for HCST to better capture product differences, prevent categorization of most foods as Tiers 2–3 and provide incentives for product reformulation.

High power density reactors based on direct cooled particle beds

International Nuclear Information System (INIS)

Powell, J.R.; Horn, F.L.

1985-01-01

Reactors based on direct cooled HTGR type particle fuel are described. The small diameter particle fuel is packed between concentric porous cylinders to make annular fuel elements, with the inlet coolant gas flowing inwards. Hot exit gas flows out long the central channel of each element. Because of the very large heat transfer area in the packed beds, power densities in particle bed reactors (PBR's) are extremely high resulting in compact, lightweight systems. Coolant exit temperatures are high, because of the ceramic fuel temperature capabilities, and the reactors can be ramped to full power and temperature very rapidly. PBR systems can generate very high burst power levels using open cycle hydrogen coolant, or high continuous powers using closed cycle helium coolant. PBR technology is described and development requirements assessed. 12 figs

Rôle et limites des tiers-lieux dans la fabrique des villes contemporaines

OpenAIRE

Besson, Raphaël

2017-01-01

La notion de tiers-lieux se développe de manière essentiellement empirique. Elle recouvre des réalités multiples, comme des projets de coworking spaces, de living labs et de fab labs. Certains tiers-lieux s’intéressent tout particulièrement à la ville et aux nouvelles conditions de la fabrique urbaine. En s’appuyant sur des méthodes d’innovation ouverte et le potentiel des outils numériques, ces tiers-lieux défendent l’idée d’un urbanisme qui ne soit plus le patrimoine exclusif d’experts, mai...

A four-tier problem-solving scaffold to teach pain management in dental school.

Science.gov (United States)

Ivanoff, Chris S; Hottel, Timothy L

2013-06-01

Pain constitutes a major reason patients pursue dental treatment. This article presents a novel curriculum to provide dental students comprehensive training in the management of pain. The curriculum's four-tier scaffold combines traditional and problem-based learning to improve students' diagnostic, pharmacotherapeutic, and assessment skills to optimize decision making when treating pain. Tier 1 provides underpinning knowledge of pain mechanisms with traditional and contextualized instruction by integrating clinical correlations and studying worked cases that stimulate clinical thinking. Tier 2 develops critical decision making skills through self-directed learning and actively solving problem-based cases. Tier 3 exposes students to management approaches taken in allied health fields and cultivates interdisciplinary communication skills. Tier 4 provides a "knowledge and experience synthesis" by rotating students through community pain clinics to practice their assessment skills. This combined teaching approach aims to increase critical thinking and problem-solving skills to assist dental graduates in better management of pain throughout their careers. Dental curricula that have moved to comprehensive care/private practice models are well-suited for this educational approach. The goal of this article is to encourage dental schools to integrate pain management into their curricula, to develop pain management curriculum resources for dental students, and to provide leadership for change in pain management education.

Materials for high temperature reactor vessels

International Nuclear Information System (INIS)

Buenaventura Pouyfaucon, A.

2004-01-01

Within the 5th Euraton Framework Programme, a big effort is being made to promote and consolidate the development of the High Temperature Reactor (HTR). Empresarios Agrupados is participating in this project and among others, also forms part of the HTR-M project Materials for HTRs. This paper summarises the work carried out by Empresarios Agrupados regarding the material selection of the HTR Reactor Pressure Vessel (RPV). The possible candidate materials and the most promising ones are discussed. Design aspects such as the RPV sensitive zones and material damage mechanisms are considered. Finally, the applicability of the existing design Codes and Standards for the design of the HTR RPV is also discussed. (Author)

Small high temperature gas-cooled reactors with innovative nuclear burning

International Nuclear Information System (INIS)

Liem, Peng Hong; Ismail; Sekimoto, Hiroshi

2008-01-01

Since the innovative concept of CANDLE (Constant Axial shape of Neutron Flux, nuclide densities and power shape During Life of Energy producing reactor) burning strategy was proposed, intensive research works have been continuously conducted to evaluate the feasibility and the performance of the burning strategy on both fast and thermal reactors. We learned that one potential application of the burning strategy for thermal reactors is for the High Temperature Gas-Cooled Reactors (HTGR) with prismatic/block-type fuel elements. Several characteristics of CANDLE burning strategy such as constant reactor characteristics during burn-up, no need for burn-up reactivity control mechanism, proportionality of core height with core lifetime, sub-criticality of fresh fuel elements, etc. enable us to design small sized HTGR with a high degree of safety easiness of operation and maintenance, and long core lifetime which are required for introducing the reactors into remote areas or developing countries with limited infrastructures and resources. In the present work, we report our evaluation results on small sized block-type HTGR designs with CANDLE burning strategy and compared with other existing small HTGR designs including the ones with pebble fuel elements, under both uranium and thorium fuel cycles. (author)

Investigation of structural materials of reactors using high-energy heavy-ion irradiations

International Nuclear Information System (INIS)

Wang Zhiguang

2007-01-01

Radiation damage in structural materials of fission/fusion reactors is mainly attributed to the evolution of intensive atom displacement damage induced by energetic particles (n, α and/or fission fragments) and high-rate helium doping by direct α particle bombardments and/or (n, α) reactions. It can cause severe degradation of reactor structural materials such as surface blistering, bulk void swelling, deformation, fatigue, embrittlement, stress erosion corrosion and so on that will significantly affect the operation safety of reactors. However, up to now, behavior of structural materials at the end of their service can hardly be fully tested in a real reactor. In the present work, damage process in reactor structural materials is briefly introduced, then the advantages of energetic ion implantation/irradiation especially high-energy heavy ion irradiation are discussed, and several typical examples on simulation of radiation effects in reactor candidate structural materials using high-energy heavy ion irradiations are pronounced. Experimental results and theoretical analysis suggested that irradiation with energetic particles especially high-energy heavy ions is very useful technique for simulating the evolution of microstructures and macro-properties of reactor structural materials. Furthermore, an on-going plan of material irradiation experiments using high energy H- and He-ions based on the Heavy Ion Research Facilities in Lanzhou (HIRFL) is also briefly interpreted. (authors)

Potential uses of high gradient magnetic filtration for high-temperature water purification in boiling water reactors

International Nuclear Information System (INIS)

Elliott, H.H.; Holloway, J.H.; Abbott, D.G.

1979-01-01

Studies of various high-temperature filter devices indicate a potentially positive impact for high gradient magnetic filtration on boiling water reactor radiation level reduction. Test results on in-plant water composition and impurity crystallography are presented for several typical boiling water reactors (BWRs) on plant streams where high-temperature filtration may be particularly beneficial. An experimental model on the removal of red iron oxide (hematite) from simulated reactor water with a high gradient magnetic filter is presented, as well as the scale-up parameters used to predict the filtration efficiency on various high temperature, in-plant streams. Numerical examples are given to illustrate the crud removal potential of high gradient magnetic filters installed at alternative stream locations under typical, steady-state, plant operating conditions

High conversion heavy water moderated reactor

International Nuclear Information System (INIS)

Miyawaki, Yoshio; Wakabayashi, Toshio.

1989-01-01

In the present invention, fuel rods using uranium-plutonium oxide mixture fuels are arranged in a square lattice at the same pitch as that in light water cooled reactor and heavy water moderators are used. Accordingly, the volume ratio (Vm/Vf) between the moderator and the fuel can be, for example, of about 2. When heavy water is used for the moderator (coolant), since the moderating effect of heavy water is lower than that of light water, a high conversion ratio of not less than 0.8 can be obtained even if the fuel rod arrangement is equal to that of PWR (Vm/Vf about 2). Accordingly, it is possible to avoid problems caused by dense arrangement of fuel rods as in high conversion rate light water cooled reactors. That is, there are no more troubles in view of thermal hydrodynamic characteristics, re-flooding upon loss of coolant accident, etc., as well as the fuel production cost is not increased. (K.M.)

Tier 3 multidisciplinary medical weight management improves outcome of Roux-en-Y gastric bypass surgery.

Science.gov (United States)

Patel, P; Hartland, A; Hollis, A; Ali, R; Elshaw, A; Jain, S; Khan, A; Mirza, S

2015-04-01

In 2013 the Department of Health specified eligibility for bariatric surgery funded by the National Health Service. This included a mandatory specification that patients first complete a Tier 3 medical weight management programme. The clinical effectiveness of this recommendation has not been evaluated previously. Our bariatric centre has provided a Tier 3 programme six months prior to bariatric surgery since 2009. The aim of our retrospective study was to compare weight loss in two cohorts: Roux-en-Y gastric bypass only (RYGB only cohort) versus Tier 3 weight management followed by RYGB (Tier 3 cohort). A total of 110 patients were selected for the study: 66 in the RYGB only cohort and 44 in the Tier 3 cohort. Patients in both cohorts were matched for age, sex, preoperative body mass index and pre-existing co-morbidities. The principal variable was therefore whether they undertook the weight management programme prior to RYGB. Patients from both cohorts were followed up at 6 and 12 months to assess weight loss. The mean weight loss at 6 months for the Tier 3 cohort was 31% (range: 18-69%, standard deviation [SD]: 0.10 percentage points) compared with 23% (range: 4-93%, SD: 0.12 percentage points) for the RYGB only cohort (p=0.0002). The mean weight loss at 12 months for the Tier 3 cohort was 34% (range: 17-51%, SD: 0.09 percentage points) compared with 27% (range: 14-48%, SD: 0.87 percentage points) in the RYGB only cohort (p=0.0037). Our study revealed that in our matched cohorts, patients receiving Tier 3 specialist medical weight management input prior to RYGB lost significantly more weight at 6 and 12 months than RYGB only patients. This confirms the clinical efficacy of such a weight management programme prior to gastric bypass surgery and supports its inclusion in eligibility criteria for bariatric surgery.

Mathematical modeling of high-rate Anammox UASB reactor based on granular packing patterns

International Nuclear Information System (INIS)

Tang, Chong-Jian; He, Rui; Zheng, Ping; Chai, Li-Yuan; Min, Xiao-Bo

2013-01-01

Highlights: ► A novel model was conducted to estimate volumetric nitrogen conversion rates. ► The packing patterns of the granules in Anammox reactor are investigated. ► The simple cubic packing pattern was simulated in high-rate Anammox UASB reactor. ► Operational strategies concerning sludge concentration were proposed by the modeling. -- Abstract: A novel mathematical model was developed to estimate the volumetric nitrogen conversion rates of a high-rate Anammox UASB reactor based on the packing patterns of granular sludge. A series of relationships among granular packing density, sludge concentration, hydraulic retention time and volumetric conversion rate were constructed to correlate Anammox reactor performance with granular packing patterns. It was suggested that the Anammox granules packed as the equivalent simple cubic pattern in high-rate UASB reactor with packing density of 50–55%, which not only accommodated a high concentration of sludge inside the reactor, but also provided large pore volume, thus prolonging the actual substrate conversion time. Results also indicated that it was necessary to improve Anammox reactor performance by enhancing substrate loading when sludge concentration was higher than 37.8 gVSS/L. The established model was carefully calibrated and verified, and it well simulated the performance of granule-based high-rate Anammox UASB reactor

Mathematical modeling of high-rate Anammox UASB reactor based on granular packing patterns

Energy Technology Data Exchange (ETDEWEB)

Tang, Chong-Jian, E-mail: chjtangzju@yahoo.com.cn [Department of Environmental Engineering, School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha 410083 (China); He, Rui; Zheng, Ping [Department of Environmental Engineering, Zhejiang University, Zijingang Campus, Hangzhou 310058 (China); Chai, Li-Yuan; Min, Xiao-Bo [Department of Environmental Engineering, School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha 410083 (China)

2013-04-15

Highlights: ► A novel model was conducted to estimate volumetric nitrogen conversion rates. ► The packing patterns of the granules in Anammox reactor are investigated. ► The simple cubic packing pattern was simulated in high-rate Anammox UASB reactor. ► Operational strategies concerning sludge concentration were proposed by the modeling. -- Abstract: A novel mathematical model was developed to estimate the volumetric nitrogen conversion rates of a high-rate Anammox UASB reactor based on the packing patterns of granular sludge. A series of relationships among granular packing density, sludge concentration, hydraulic retention time and volumetric conversion rate were constructed to correlate Anammox reactor performance with granular packing patterns. It was suggested that the Anammox granules packed as the equivalent simple cubic pattern in high-rate UASB reactor with packing density of 50–55%, which not only accommodated a high concentration of sludge inside the reactor, but also provided large pore volume, thus prolonging the actual substrate conversion time. Results also indicated that it was necessary to improve Anammox reactor performance by enhancing substrate loading when sludge concentration was higher than 37.8 gVSS/L. The established model was carefully calibrated and verified, and it well simulated the performance of granule-based high-rate Anammox UASB reactor.

Three-tiered risk stratification model to predict progression in Barrett's esophagus using epigenetic and clinical features.

Directory of Open Access Journals (Sweden)

Fumiaki Sato

2008-04-01

Full Text Available Barrett's esophagus predisposes to esophageal adenocarcinoma. However, the value of endoscopic surveillance in Barrett's esophagus has been debated because of the low incidence of esophageal adenocarcinoma in Barrett's esophagus. Moreover, high inter-observer and sampling-dependent variation in the histologic staging of dysplasia make clinical risk assessment problematic. In this study, we developed a 3-tiered risk stratification strategy, based on systematically selected epigenetic and clinical parameters, to improve Barrett's esophagus surveillance efficiency.We defined high-grade dysplasia as endpoint of progression, and Barrett's esophagus progressor patients as Barrett's esophagus patients with either no dysplasia or low-grade dysplasia who later developed high-grade dysplasia or esophageal adenocarcinoma. We analyzed 4 epigenetic and 3 clinical parameters in 118 Barrett's esophagus tissues obtained from 35 progressor and 27 non-progressor Barrett's esophagus patients from Baltimore Veterans Affairs Maryland Health Care Systems and Mayo Clinic. Based on 2-year and 4-year prediction models using linear discriminant analysis (area under the receiver-operator characteristic (ROC curve: 0.8386 and 0.7910, respectively, Barrett's esophagus specimens were stratified into high-risk (HR, intermediate-risk (IR, or low-risk (LR groups. This 3-tiered stratification method retained both the high specificity of the 2-year model and the high sensitivity of the 4-year model. Progression-free survivals differed significantly among the 3 risk groups, with p = 0.0022 (HR vs. IR and p<0.0001 (HR or IR vs. LR. Incremental value analyses demonstrated that the number of methylated genes contributed most influentially to prediction accuracy.This 3-tiered risk stratification strategy has the potential to exert a profound impact on Barrett's esophagus surveillance accuracy and efficiency.

IRPhE-DRAGON-DPR, OECD High Temperature Reactor Dragon Project, Primary Documents

International Nuclear Information System (INIS)

2004-01-01

Description: The DRAGON Reactor Experiment (DRE): The first demonstration High temperature gas reactor (HTGR) was built in the 1960's. Thirteen OECD countries began a project in 1959 to build an experimental reactor known as Dragon at Winfrith in the UK. The reactor - which operated successfully between 1966 and 1975 - had a thermal output of 20 MW and achieved a gas outlet temperature of 750 deg. C. The High Temperature Reactor concept, if it justified its expectations, was seen as having its place as an advanced thermal reactor between the current thermal reactor types such as the PWR, BWR, and AGR and the sodium cooled fast breeder reactor. It was expected that the HTR would offer better thermal efficiency, better uranium utilisation, either with low enriched uranium fuel or high enriched uranium thorium fuel, better inherent safety and lower unit power costs. In the event all these potential advantages were demonstrated to be in principle achievable. This view is still shared today. In fact Very High Temperature Reactors is one of the concepts retained for Generation IV. Projects on constructing Modular Pebble Bed Reactors are under way. Here all available Dragon Project Reports (DPR) - approximately 1000 - are collected in electronic form. An index points to the reports (PDF format); each table in the report is accessible in EXCEL format with the aim of facilitating access to the data. These reports describe the design, experiments and modelling carried out over a period of 17 years. 2 - Related or auxiliary information: IRPHE-HTR-ARCH-01, Archive of HTR Primary Documents NEA-1728/01. 3 - Software requirements: Acrobat Reader, Microsoft Word, HTML Browser required

Using a Two-Tier Test to Assess Students' Understanding and Alternative Conceptions of Cyber Copyright Laws

Science.gov (United States)

Chou, Chien; Chan, Pei-Shan; Wu, Huan-Chueh

2007-01-01

The purpose of this study is to explore students' understanding of cyber copyright laws. This study developed a two-tier test with 10 two-level multiple-choice questions. The first tier presented a real-case scenario and asked whether the conduct was acceptable whereas the second-tier provided reasons to justify the conduct. Students in Taiwan…

Fuel management at the Petten high flux reactor

International Nuclear Information System (INIS)

Thijssen, P.J.M.

1999-01-01

Several years ago the shipment of spent fuel of the High Flux Reactor (HFR) at Petten has come to a standstill resulting in an ever growing stock of fuel elements that are labelled 'fully burnt up'. Examination of those elements showed that a reasonably number of them have a relatively high 235 U mass left. A reactor physics analysis showed that the use of such elements in the peripheral core zone allows the loading of four instead of five fresh fuel elements in many cycle cores. For the assessment of safety and performance parameters of HFR cores a new calculational tool is being developed. It is based on AEA Technology's Reactor physics code suite Winfrith Improved Multigroup Scheme (WIMS). NRG produced pre- and post-processing facilities to feed input data into WIMS's 2D transport code CACTUS and to extract relevant parameters from the output. The processing facilities can be used for many different types of application. (author)

Generation IV Reactors Integrated Materials Technology Program Plan: Focus on Very High Temperature Reactor Materials

Energy Technology Data Exchange (ETDEWEB)

Corwin, William R [ORNL; Burchell, Timothy D [ORNL; Katoh, Yutai [ORNL; McGreevy, Timothy E [ORNL; Nanstad, Randy K [ORNL; Ren, Weiju [ORNL; Snead, Lance Lewis [ORNL; Wilson, Dane F [ORNL

2008-08-01

Since 2002, the Department of Energy's (DOE's) Generation IV Nuclear Energy Systems (Gen IV) Program has addressed the research and development (R&D) necessary to support next-generation nuclear energy systems. The six most promising systems identified for next-generation nuclear energy are described within this roadmap. Two employ a thermal neutron spectrum with coolants and temperatures that enable hydrogen or electricity production with high efficiency (the Supercritical Water Reactor-SCWR and the Very High Temperature Reactor-VHTR). Three employ a fast neutron spectrum to enable more effective management of actinides through recycling of most components in the discharged fuel (the Gas-cooled Fast Reactor-GFR, the Lead-cooled Fast Reactor-LFR, and the Sodium-cooled Fast Reactor-SFR). The Molten Salt Reactor (MSR) employs a circulating liquid fuel mixture that offers considerable flexibility for recycling actinides and may provide an alternative to accelerator-driven systems. At the inception of DOE's Gen IV program, it was decided to significantly pursue five of the six concepts identified in the Gen IV roadmap to determine which of them was most appropriate to meet the needs of future U.S. nuclear power generation. In particular, evaluation of the highly efficient thermal SCWR and VHTR reactors was initiated primarily for energy production, and evaluation of the three fast reactor concepts, SFR, LFR, and GFR, was begun to assess viability for both energy production and their potential contribution to closing the fuel cycle. Within the Gen IV Program itself, only the VHTR class of reactors was selected for continued development. Hence, this document will address the multiple activities under the Gen IV program that contribute to the development of the VHTR. A few major technologies have been recognized by DOE as necessary to enable the deployment of the next generation of advanced nuclear reactors, including the development and qualification of

From high enriched to low enriched uranium fuel in research reactors

Energy Technology Data Exchange (ETDEWEB)

Van Den Berghe, S.; Leenaers, A.; Koonen, E.; Moons, F.; Sannen, L. [Nuclear Materials Science Institute, SCK.CEN, Boeretang 200, B-2400 Mol (Belgium)

2010-07-01

Since the 1970's, global efforts have been going on to replace the high-enriched (>90% {sup 235}U), low-density UAlx research reactor fuel with high-density, low enriched (<20% {sup 235}U) replacements. This search is driven by the attempt to reduce the civil use of high-enriched material because of proliferation risks and terrorist threats. American initiatives, such as the Global Threat Reduction Initiative (GTRI) and the Reduced Enrichment for Research and Test Reactors (RERTR) program have triggered the development of reliable low-enriched fuel types for these reactors, which can replace the high enriched ones without loss of performance. Most success has presently been obtained with U{sub 3}Si{sub 2} dispersion fuel, which is currently used in many research reactors in the world. However, efforts to search for a replacement with even higher density, which will also allow the conversion of some high flux research reactors that currently cannot change to U{sub 3}Si{sub 2} (eg. BR2 in Belgium), have continued and are for the moment mainly directed towards the U(Mo) alloy fuel (7-10 w% Mo). This paper provides an overview of the past efforts and presents the current status of the U(Mo) development. (authors)

From high enriched to low enriched uranium fuel in research reactors

International Nuclear Information System (INIS)

Van Den Berghe, S.; Leenaers, A.; Koonen, E.; Moons, F.; Sannen, L.

2010-01-01

Since the 1970's, global efforts have been going on to replace the high-enriched (>90% 235 U), low-density UAlx research reactor fuel with high-density, low enriched ( 235 U) replacements. This search is driven by the attempt to reduce the civil use of high-enriched material because of proliferation risks and terrorist threats. American initiatives, such as the Global Threat Reduction Initiative (GTRI) and the Reduced Enrichment for Research and Test Reactors (RERTR) program have triggered the development of reliable low-enriched fuel types for these reactors, which can replace the high enriched ones without loss of performance. Most success has presently been obtained with U 3 Si 2 dispersion fuel, which is currently used in many research reactors in the world. However, efforts to search for a replacement with even higher density, which will also allow the conversion of some high flux research reactors that currently cannot change to U 3 Si 2 (eg. BR2 in Belgium), have continued and are for the moment mainly directed towards the U(Mo) alloy fuel (7-10 w% Mo). This paper provides an overview of the past efforts and presents the current status of the U(Mo) development. (authors)

A high temperature reactor could be used to eliminate the Russian military plutonium

International Nuclear Information System (INIS)

Foucher, N.

1999-01-01

The GT-MHR reactor (Gas Turbine Modular Helium Reactor) aims the double objective to eliminate the Russian plutonium coming from weapons, ( until 3 tons by year) and to produce a competitive energy from a small-scale power reactor with a nuclear fuel that can be of different type (plutonium or uranium). This reactor has several advantages: a high yield (47%) as every high temperature reactor and to be used in combined cycle, a high level of safety because of its ability to evacuate the residual power in a totally passive way and because of the nature of its fuel that is made of ceramics with a very high melting point that is to say no possibility of core melt. The fission products are contained in the ceramics so that reactor cannot disseminate radioactivity in its structure and consequently does not induce irradiation for the personnel. (N.C.)

Studies on high temperature research reactor in China

Energy Technology Data Exchange (ETDEWEB)

Xu Yuanhui; Zuo Kanfen [Institute of Nuclear Energy Technology, Tsinghua Univ., Beijing (China)

1999-08-01

China recognises the advantages of Modular HTGRs and has chosen Modular HTGRs as one of advanced reactors to be developed for the further intensive utilisation of nuclear power in the next century. In energy supply systems of the next century, HTGR is supposed to serve: 1. as supplement to water-cooled reactors for electricity generation and 2. as environmentally friendly heat source providing process heat at different temperatures for various applications like heavy oil recovery, coal gasification and liquefaction, etc.. The 10 MW High Temperature Gas-cooled Reactor (HTR-10) is a major project in the energy sector of the Chinese National High Technology Programme as the first step of development of Modular HTGRs in China. Its main objectives are: 1. to acquire know-how in the design, construction and operation of HTGRs, 2. to establish an irradiation and experimental facility, 3. to demonstrate the inherent safety features of Modular HTGR, 4. to test electricity and heat co-generation and closed cycle gas turbine technology and 5. to do research and development work on the nuclear process heat application. Now the HTR-10 is being constructed at the site of Institute of Nuclear Energy Technology (INET). The HTR-10 project is to be carried out in two phases. In the first phase, the reactor with an coolant outlet temperature of 700degC will be coupled with a steam generator providing steam for a steam turbine cycle which works on an electricity and heat co-generation basis. In the second phase, the reactor coolant outlet temperature is planned to be raised to 900degC. As gas turbine cycle and a steam reformer will be coupled to the reactor in addition to the steam turbine cycle. (author)

Studies on high temperature research reactor in China

International Nuclear Information System (INIS)

Xu Yuanhui; Zuo Kanfen

1999-01-01

China recognises the advantages of Modular HTGRs and has chosen Modular HTGRs as one of advanced reactors to be developed for the further intensive utilisation of nuclear power in the next century. In energy supply systems of the next century, HTGR is supposed to serve: 1. as supplement to water-cooled reactors for electricity generation and 2. as environmentally friendly heat source providing process heat at different temperatures for various applications like heavy oil recovery, coal gasification and liquefaction, etc.. The 10 MW High Temperature Gas-cooled Reactor (HTR-10) is a major project in the energy sector of the Chinese National High Technology Programme as the first step of development of Modular HTGRs in China. Its main objectives are: 1. to acquire know-how in the design, construction and operation of HTGRs, 2. to establish an irradiation and experimental facility, 3. to demonstrate the inherent safety features of Modular HTGR, 4. to test electricity and heat co-generation and closed cycle gas turbine technology and 5. to do research and development work on the nuclear process heat application. Now the HTR-10 is being constructed at the site of Institute of Nuclear Energy Technology (INET). The HTR-10 project is to be carried out in two phases. In the first phase, the reactor with an coolant outlet temperature of 700degC will be coupled with a steam generator providing steam for a steam turbine cycle which works on an electricity and heat co-generation basis. In the second phase, the reactor coolant outlet temperature is planned to be raised to 900degC. As gas turbine cycle and a steam reformer will be coupled to the reactor in addition to the steam turbine cycle. (author)

Modular High Temperature Gas-Cooled Reactor Safety Basis and Approach

Energy Technology Data Exchange (ETDEWEB)

David Petti; Jim Kinsey; Dave Alberstein

2014-01-01

Various international efforts are underway to assess the safety of advanced nuclear reactor designs. For example, the International Atomic Energy Agency has recently held its first Consultancy Meeting on a new cooperative research program on high temperature gas-cooled reactor (HTGR) safety. Furthermore, the Generation IV International Forum Reactor Safety Working Group has recently developed a methodology, called the Integrated Safety Assessment Methodology, for use in Generation IV advanced reactor technology development, design, and design review. A risk and safety assessment white paper is under development with respect to the Very High Temperature Reactor to pilot the Integrated Safety Assessment Methodology and to demonstrate its validity and feasibility. To support such efforts, this information paper on the modular HTGR safety basis and approach has been prepared. The paper provides a summary level introduction to HTGR history, public safety objectives, inherent and passive safety features, radionuclide release barriers, functional safety approach, and risk-informed safety approach. The information in this paper is intended to further the understanding of the modular HTGR safety approach. The paper gives those involved in the assessment of advanced reactor designs an opportunity to assess an advanced design that has already received extensive review by regulatory authorities and to judge the utility of recently proposed new methods for advanced reactor safety assessment such as the Integrated Safety Assessment Methodology.

75 FR 33389 - TierOne Bank Lincoln, Nebraska; Notice of Appointment of Receiver

Science.gov (United States)

2010-06-11

... DEPARTMENT OF THE TREASURY Office of Thrift Supervision TierOne Bank Lincoln, Nebraska; Notice of... the Home Owners' Loan Act, the Office of Thrift Supervision has duly appointed the Federal Deposit Insurance Corporation as sole Receiver for TierOne Bank, Lincoln, Nebraska, (OTS No. 03309), on June 4, 2010...

20 CFR 209.14 - Report of separation allowances subject to tier II taxation.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Report of separation allowances subject to tier II taxation. 209.14 Section 209.14 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER... separation allowances subject to tier II taxation. For any employee who is paid a separation payment, the...

Mitigate Strategy of Very High Temperature Reactor Air-ingress Accident

Energy Technology Data Exchange (ETDEWEB)

Ham, Tae Kyu [KHNP CRI, Daejeon (Korea, Republic of); Arcilesi, David J.; Sun, Xiaodong; Christensen, Richard N. [The Ohio State University, Columbus (United States); Oh, Chang H.; Kim, Eung S. [Idaho National Laboratory, Idaho (United States)

2016-10-15

A critical safety event of the Very High Temperature Reactor (VHTR) is a loss-of-coolant accident (LOCA). Since a VHTR uses graphite as a core structure, if there is a break on the pressure vessel, the air in the reactor cavity could ingress into the reactor core. The worst case scenario of the accident is initiated by a double-ended guillotine break of the cross vessel that connects the reactor vessel and the power conversion unit. The operating pressures in the vessel and containment are about 7 and 0.1 MPa, respectively. In the VHTR, the reactor pressure vessel is located within a reactor cavity which is filled with air during normal operation. Therefore, the air-helium mixture in the cavity may ingress into the reactor pressure vessel after the depressurization process. In this paper, a commercial computational fluid dynamics (CFD) tool, FLUENT, was used to figure out air-ingress mitigation strategies in the gas-turbine modular helium reactor (GT-MHR) designed by General Atomics, Inc. After depressurization, there is almost no air in the reactor cavity; however, the air could flow back to the reactor cavity since the reactor cavity is placed in the lowest place in the reactor building. The heavier air could flow to the reactor cavity through free surface areas in the reactor building. Therefore, Argon gas injection in the reactor cavity is introduced. The injected argon would prevent the flow by pressurizing the reactor cavity initially, and eventually it prevents the flow by making the gas a heavier density than air in the reactor cavity. The gate opens when the reactor cavity is pressurized during the depressurization and it closes by gravity when the depressurization is terminated so that it can slow down the air flow to the reactor cavity.

Epidemiology program at the Savannah River Plant: a tiered approach to research

International Nuclear Information System (INIS)

Fayerweather, W.E.

1984-01-01

The epidemiology program at the Savannah River Plant (SRP) uses a tiered approach to research. As research progresses from lower through higher tiers, there is a corresponding increase in study complexity, cost, and time commitment. The approach provides a useful strategy for directing research efforts towards those employee subgroups and health endpoints that can benefit most from more in-depth studies. A variety of potential exposures, health endpoints, and employee subgroups have been and continued to be studied by research groups such as Oak Ridge Associated Universities, Los Alamos National Laboratories, Centers for Disease Control, SRP's Occupational Health Technology, and the Du Pont Company's corporate Epidemiology Section. These studies are discussed in the context of a tiered approach to research

Proliferation resistance assessment of high temperature gas reactors

Energy Technology Data Exchange (ETDEWEB)

Chikamatsu N, M. A. [Instituto Tecnologico y de Estudios Superiores de Monterrey, Campus Santa Fe, Av. Carlos Lazo No. 100, Santa Fe, 01389 Mexico D. F. (Mexico); Puente E, F., E-mail: midori.chika@gmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2014-10-15

The Generation IV International Forum has established different objectives for the new generation of reactors to accomplish. These objectives are focused on sustain ability, safety, economics and proliferation resistance. This paper is focused on how the proliferation resistance of the High Temperature Gas Reactors (HTGR) is assessed and the advantages that these reactors present currently. In this paper, the focus will be on explaining why such reactors, HTGR, can achieve the goals established by the GIF and can present a viable option in terms of proliferation resistance, which is an issue of great importance in the field of nuclear energy generation. The reason why the HTGR are being targeted in this writing is that these reactors are versatile, and present different options from modular reactors to reactors with the same size as the ones that are being operated today. Besides their versatility, the HTGR has designed features that might improve on the overall sustain ability of the nuclear reactors. This is because the type of safety features and materials that are used open up options for industrial processes to be carried out; cogeneration for instance. There is a small section that mentions how HTGR s are being developed in the international sector in order to present the current world view in this type of technology and the further developments that are being sought. For the proliferation resistance section, the focus is on both the intrinsic and the extrinsic features of the nuclear systems. The paper presents a comparison between the features of Light Water Reactors (LWR) and the HTGR in order to be able to properly compare the most used technology today and one that is gaining international interest. (Author)

Proliferation resistance assessment of high temperature gas reactors

International Nuclear Information System (INIS)

Chikamatsu N, M. A.; Puente E, F.

2014-10-01

The Generation IV International Forum has established different objectives for the new generation of reactors to accomplish. These objectives are focused on sustain ability, safety, economics and proliferation resistance. This paper is focused on how the proliferation resistance of the High Temperature Gas Reactors (HTGR) is assessed and the advantages that these reactors present currently. In this paper, the focus will be on explaining why such reactors, HTGR, can achieve the goals established by the GIF and can present a viable option in terms of proliferation resistance, which is an issue of great importance in the field of nuclear energy generation. The reason why the HTGR are being targeted in this writing is that these reactors are versatile, and present different options from modular reactors to reactors with the same size as the ones that are being operated today. Besides their versatility, the HTGR has designed features that might improve on the overall sustain ability of the nuclear reactors. This is because the type of safety features and materials that are used open up options for industrial processes to be carried out; cogeneration for instance. There is a small section that mentions how HTGR s are being developed in the international sector in order to present the current world view in this type of technology and the further developments that are being sought. For the proliferation resistance section, the focus is on both the intrinsic and the extrinsic features of the nuclear systems. The paper presents a comparison between the features of Light Water Reactors (LWR) and the HTGR in order to be able to properly compare the most used technology today and one that is gaining international interest. (Author)

New deployment of high temperature gas-cooled reactor

International Nuclear Information System (INIS)

Sekimoto, Hiroshi; Tsuchie, Yasuo; Kunitomi, Kazuhiko; Shiozawa, Shusaku; Konuki, Kaoru; Inagaki, Yoshiyuki; Hayakawa, Hitoshi

2002-01-01

The high temperature gas-cooled reactor (HTGR) is now under a condition difficult to know it well, because of considering not only power generation, but also diverse applications of its nuclear heat, of having extremely different safe principle from that of conventional reactors, of having two types of pebble-bed and block which are extremely different types, of promoting its construction plan in South Africa, of including its application to disposition of Russian surplus weapons plutonium of less reporting HTTR in Japan in spite of its full operation, and so on. However, HTGR is expected for an extremely important nuclear reactor aiming at the next coming one of LWR. HTGR which is late started and developed under complete private leading, is strongly conscious at environmental problem since its beginning. Before 30 years when large scale HTGR was expected to operate, it advertised a merit to reduce wasted heat because of its high temperature. As ratio occupied by electricity expands among application of energies, ratio occupied by the other energies are larger. When considering applications except electric power, high temperature thermal energy from HTGR can be thought wider applications than that from LWR and so on. (G.K.)

High Temperature Gas-Cooled Test Reactor Point Design: Summary Report

Energy Technology Data Exchange (ETDEWEB)

Sterbentz, James William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bayless, Paul David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Nelson, Lee Orville [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gougar, Hans David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kinsey, J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Strydom, Gerhard [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-03-01

A point design has been developed for a 200-MW high-temperature gas-cooled test reactor. The point design concept uses standard prismatic blocks and 15.5% enriched uranium oxycarbide fuel. Reactor physics and thermal-hydraulics simulations have been performed to characterize the capabilities of the design. In addition to the technical data, overviews are provided on the technology readiness level, licensing approach, and costs of the test reactor point design.

High Temperature Gas-Cooled Test Reactor Point Design: Summary Report

Energy Technology Data Exchange (ETDEWEB)

Sterbentz, James William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bayless, Paul David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Nelson, Lee Orville [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gougar, Hans David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Strydom, Gerhard [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-01-01

A point design has been developed for a 200-MW high-temperature gas-cooled test reactor. The point design concept uses standard prismatic blocks and 15.5% enriched uranium oxycarbide fuel. Reactor physics and thermal-hydraulics simulations have been performed to characterize the capabilities of the design. In addition to the technical data, overviews are provided on the technology readiness level, licensing approach, and costs of the test reactor point design.

Alcohol synthesis in a high-temperature slurry reactor

Energy Technology Data Exchange (ETDEWEB)

Roberts, G.W.; Marquez, M.A.; McCutchen, M.S. [North Carolina State Univ., Raleigh, NC (United States)

1995-12-31

The overall objective of this contract is to develop improved process and catalyst technology for producing higher alcohols from synthesis gas or its derivatives. Recent research has been focused on developing a slurry reactor that can operate at temperatures up to about 400{degrees}C and on evaluating the so-called {open_quotes}high pressure{close_quotes} methanol synthesis catalyst using this reactor. A laboratory stirred autoclave reactor has been developed that is capable of operating at temperatures up to 400{degrees}C and pressures of at least 170 atm. The overhead system on the reactor is designed so that the temperature of the gas leaving the system can be closely controlled. An external liquid-level detector is installed on the gas/liquid separator and a pump is used to return condensed slurry liquid from the separator to the reactor. In order to ensure that gas/liquid mass transfer does not influence the observed reaction rate, it was necessary to feed the synthesis gas below the level of the agitator. The performance of a commercial {open_quotes}high pressure {close_quotes} methanol synthesis catalyst, the so-called {open_quotes}zinc chromite{close_quotes} catalyst, has been characterized over a range of temperature from 275 to 400{degrees}C, a range of pressure from 70 to 170 atm., a range of H{sub 2}/CO ratios from 0.5 to 2.0 and a range of space velocities from 2500 to 10,000 sL/kg.(catalyst),hr. Towards the lower end of the temperature range, methanol was the only significant product.

Operation of the High Flux Reactor. Annual report 1985

International Nuclear Information System (INIS)

1985-01-01

This year was characterized by the end of a major rebuilding of the installation during which the reactor vessel and its peripheral components were replaced by new and redesigned equipment. Both operational safety and experimental use were largely improved by the replacement. The reactor went back to routine operation on February 14, 1985, and has been operating without problem since then. All performance parameters were met. Other upgrading actions started during the year concerned new heat exchangers and improvements to the reactor building complex. The experimental load of the High Flux Reactor reached a satisfactory level with an average of 57%. New developments aimed at future safety related irradiation tests and at novel applications of neutrons from the horizontal beam tubes. A unique remote encapsulation hot cell facility became available adding new possibilities for fast breeder fuel testing and for intermediate specimen examination. The HFR Programme hosted an international meeting on development and use of reduced enrichment fuel for research reactors. All aspects of core physics, manufacture technology, and licensing of novel, proliferation-free, research reactor fuel were debated

Resonance integral calculations for high temperature reactors

International Nuclear Information System (INIS)

Blake, J.P.H.

1960-02-01

Methods of calculation of resonance integrals of finite dilution and temperature are given for both, homogeneous and heterogeneous geometries, together with results obtained from these methods as applied to the design of high temperature reactors. (author)

High density, high magnetic field concepts for compact fusion reactors

International Nuclear Information System (INIS)

Perkins, L.J.

1996-01-01

One rather discouraging feature of our conventional approaches to fusion energy is that they do not appear to lend themselves to a small reactor for developmental purposes. This is in contrast with the normal evolution of a new technology which typically proceeds to a full scale commercial plant via a set of graduated steps. Accordingly' several concepts concerned with dense plasma fusion systems are being studied theoretically and experimentally. A common aspect is that they employ: (a) high to very high plasma densities (∼10 16 cm -3 to ∼10 26 cm -3 ) and (b) magnetic fields. If they could be shown to be viable at high fusion Q, they could conceivably lead to compact and inexpensive commercial reactors. At least, their compactness suggests that both proof of principle experiments and development costs will be relatively inexpensive compared with the present conventional approaches. In this paper, the following concepts are considered: (1) The staged Z-pinch, (2) Liner implosion of closed-field-line configurations, (3) Magnetic ''fast'' ignition of inertial fusion targets, (4) The continuous flow Z-pinch

Fusion reactor high vacuum pumping

International Nuclear Information System (INIS)

Sedgley, D.W.; Walthers, C.R.; Jenkins, E.M.

1992-01-01

This paper reports on recent experiments which have shown the practicality of using activated carbon (coconut charcoal) at 4K to pump helium and hydrogen isotopes for a fusion reactor. Both speed and capacity for deuterium/helium and tritium/helium-3 mixtures were satisfactory. The long-term effects of tritium on the charcoal/cement system developed by Grumman and LLNL was now known; therefore a program was undertaken to see what, if any, effect long-term tritium exposure has on the cryosorber. Several charcoal on aluminum test samples were subjected to six months exposure of tritium at approximately 77 K. The tritium was scanned several times with a residual gas analyzer and the speed-capacity performance of the samples was measured before, approximately one-third way through, and after the exposure. Modest effects were noted which would not seriously restrict the use of charcoal as a cryosorber for fusion reactor high-vacuum pumping applications

High temperature brazing of reactor materials

International Nuclear Information System (INIS)

Orlov, A.V.; Nechaev, V.A.; Rybkin, B.V.; Ponimash, I.D.

1990-01-01

Application of high-temperature brazing for joining products of such materials as molybdenum, tungsten, zirconium, beryllium, magnesium, nickel and aluminium alloys, graphite ceramics etc. is described. Brazing materials composition and brazed joints properties are presented. A satisfactory strength of brazed joints is detected under reactor operation temperatures and coolant and irradiation effect

High-intensity power-resolved radiation imaging of an operational nuclear reactor.

Science.gov (United States)

Beaumont, Jonathan S; Mellor, Matthew P; Villa, Mario; Joyce, Malcolm J

2015-10-09

Knowledge of the neutron distribution in a nuclear reactor is necessary to ensure the safe and efficient burnup of reactor fuel. Currently these measurements are performed by in-core systems in what are extremely hostile environments and in most reactor accident scenarios it is likely that these systems would be damaged. Here we present a compact and portable radiation imaging system with the ability to image high-intensity fast-neutron and gamma-ray fields simultaneously. This system has been deployed to image radiation fields emitted during the operation of a TRIGA test reactor allowing a spatial visualization of the internal reactor conditions to be obtained. The imaged flux in each case is found to scale linearly with reactor power indicating that this method may be used for power-resolved reactor monitoring and for the assay of ongoing nuclear criticalities in damaged nuclear reactors.

Irradiation Tests Supporting LEU Conversion of Very High Power Research Reactors in the US

Energy Technology Data Exchange (ETDEWEB)

Woolstenhulme, N. E.; Cole, J. I.; Glagolenko, I.; Holdaway, K. K.; Housley, G. K.; Rabin, B. H.

2016-10-01

The US fuel development team is developing a high density uranium-molybdenum alloy monolithic fuel to enable conversion of five high-power research reactors. Previous irradiation tests have demonstrated promising behavior for this fuel design. A series of future irradiation tests will enable selection of final fuel fabrication process and provide data to qualify the fuel at moderately-high power conditions for use in three of these five reactors. The remaining two reactors, namely the Advanced Test Reactor and High Flux Isotope Reactor, require additional irradiation tests to develop and demonstrate the fuel’s performance with even higher power conditions, complex design features, and other unique conditions. This paper reviews the program’s current irradiation testing plans for these moderately-high irradiation conditions and presents conceptual testing strategies to illustrate how subsequent irradiation tests will build upon this initial data package to enable conversion of these two very-high power research reactors.

Preliminary Neutronic Design of High Burnup OTTO Cycle Pebble Bed Reactor

OpenAIRE

Setiadipura, T; Irwanto, D; Zuhair, Zuhair

2015-01-01

The pebble bed type High Temperature Gas-cooled Reactor (HTGR) is among the interesting nuclear reactor designs in terms of safety and flexibility for co-generation applications. In addition, the strong inherent safety characteristics of the pebble bed reactor (PBR) which is based on natural mechanisms improve the simplicity of the PBR design, in particular for the Once-Through-Then-Out (OTTO) cycle PBR design. One of the important challenges of the OTTO cycle PBR design, and nuclear reactor ...

The High Flux Reactor Petten, present status and prospects

Energy Technology Data Exchange (ETDEWEB)

Ahlf, J [Institute for Advanced Materials, Joint Research Centre, Petten (Netherlands)

1990-05-01

The High Flux Reactor (HFR) in Petten, The Netherlands, is a light water cooled and moderated multipurpose research reactor of the closed-tank in pool type. It is operated with highly enriched Uranium fuel at a power of 45 MW. The reactor is owned by the European Communities and operated under contract by the Dutch ECN. The HFR programme is funded by The Netherlands and Germany, a smaller share comes from the specific programmes of the Joint Research Centre (JRC) and from third party contract work. Since its first criticality in 1961 the reactor has been continuously upgraded by implementing developments in fuel element technology and increasing the power from 20 MW to the present 45 MV. In 1984 the reactor vessel was replaced by a new one with an improved accessibility for experiments. In the following years also other ageing equipment has been replaced (primary heat exchangers, pool heat exchanger, beryllium reflector elements, nuclear and process instrumentation, uninterruptable power supply). Control room upgrading is under preparation. A new safety analysis is near to completion and will form the basis for a renewed license. The reactor is used for nuclear energy related research (structural materials and fuel irradiations for LWR's, HTR's and FBR's, fusion materials irradiations). The beam tubes are used for nuclear physics as well as solid state and materials sciences. Radioisotope production at large scale, processing of gemstones and silicon with neutrons, neutron radiography and activation analysis are actively pursued. A clinical facility for boron neutron capture therapy is being designed at one of the large cross section beam tubes. It is foreseen to operate the reactor at least for a further decade. The exploitation pattern may undergo some changes depending on the requirements of the supporting countries and the JRC programmes. (author)

The High Flux Reactor Petten, present status and prospects

International Nuclear Information System (INIS)

Ahlf, J.

1990-01-01

The High Flux Reactor (HFR) in Petten, The Netherlands, is a light water cooled and moderated multipurpose research reactor of the closed-tank in pool type. It is operated with highly enriched Uranium fuel at a power of 45 MW. The reactor is owned by the European Communities and operated under contract by the Dutch ECN. The HFR programme is funded by The Netherlands and Germany, a smaller share comes from the specific programmes of the Joint Research Centre (JRC) and from third party contract work. Since its first criticality in 1961 the reactor has been continuously upgraded by implementing developments in fuel element technology and increasing the power from 20 MW to the present 45 MV. In 1984 the reactor vessel was replaced by a new one with an improved accessibility for experiments. In the following years also other ageing equipment has been replaced (primary heat exchangers, pool heat exchanger, beryllium reflector elements, nuclear and process instrumentation, uninterruptable power supply). Control room upgrading is under preparation. A new safety analysis is near to completion and will form the basis for a renewed license. The reactor is used for nuclear energy related research (structural materials and fuel irradiations for LWR's, HTR's and FBR's, fusion materials irradiations). The beam tubes are used for nuclear physics as well as solid state and materials sciences. Radioisotope production at large scale, processing of gemstones and silicon with neutrons, neutron radiography and activation analysis are actively pursued. A clinical facility for boron neutron capture therapy is being designed at one of the large cross section beam tubes. It is foreseen to operate the reactor at least for a further decade. The exploitation pattern may undergo some changes depending on the requirements of the supporting countries and the JRC programmes. (author)

Fluoride Salt-Cooled High-Temperature Demonstration Reactor Point Design

Energy Technology Data Exchange (ETDEWEB)

Qualls, A. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brown, Nicholas R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Betzler, Benjamin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Carbajo, Juan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hale, Richard Edward [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Harrison, Thomas J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Powers, Jeffrey J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Robb, Kevin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrell, Jerry W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wysocki, Aaron J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-02-01

The fluoride salt-cooled high-temperature reactor (FHR) demonstration reactor (DR) is a concept for a salt-cooled reactor with 100 megawatts of thermal output (MWt). It would use tristructural-isotropic (TRISO) particle fuel within prismatic graphite blocks. FLiBe (2 LiF-BeF₂) is the reference primary coolant. The FHR DR is designed to be small, simple, and affordable. Development of the FHR DR is a necessary intermediate step to enable near-term commercial FHRs. Lower risk technologies are purposely included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated within an acceptable budget and schedule. These technologies include TRISO particle fuel, replaceable core structural material, the use of that same material for the primary and intermediate loops, and tube-and-shell primary-to-intermediate heat exchangers. Several preconceptual and conceptual design efforts that have been conducted on FHR concepts bear a significant influence on the FHR DR design. Specific designs include the Oak Ridge National Laboratory (ORNL) advanced high-temperature reactor (AHTR) with 3400/1500 MWt/megawatts of electric output (MWe), as well as a 125 MWt small modular AHTR (SmAHTR) from ORNL. Other important examples are the Mk1 pebble bed FHR (PB-FHR) concept from the University of California, Berkeley (UCB), and an FHR test reactor design developed at the Massachusetts Institute of Technology (MIT). The MIT FHR test reactor is based on a prismatic fuel platform and is directly relevant to the present FHR DR design effort. These FHR concepts are based on reasonable assumptions for credible commercial prototypes. The FHR DR concept also directly benefits from the operating experience of the Molten Salt Reactor Experiment (MSRE), as well as the detailed design efforts for a large molten salt reactor concept and its breeder variant, the Molten Salt Breeder Reactor. The FHR DR technology is most representative of the 3400 MWt AHTR

Emplacement feasibility of a multi-tier, expanded capacity repository at Yucca Mountain, Nevada USA

International Nuclear Information System (INIS)

Apted, Michael; Kessler, John; Fairhurst, Charles

2008-01-01

A geological repository at Yucca Mountain has been proposed for the disposal of spent fuel from the US commercial reactors and other radioactive waste. A legislative capacity of 70,000 MTHM has been set by the Nuclear Waste Policy Act of 1982, including 63,000 MTHM of commercial spent nuclear fuel (CSNF), the projected amount of CSNF that will be produced by about 2014. Policy issues remain as to how to handle waste that is generated beyond 2014 from a growing nuclear industry in the US. The Electric Power Research Institute (EPRI) is independently evaluating the technical, rather than legislative, limit of CSNF that could be safely disposed at Yucca Mountain. Geological, thermal management, safety and cost factors have been recently evaluated by EPRI (2006; 2007) for grouped emplacement drifts and/or a multi-tier repository. EPRI's evaluation of emplacement feasibility for a multi-tier concept is described here. Expanded capacity concepts as envisioned for Yucca Mountain (EPRI, 2006; 2007) assume excavation of one or two additional levels of drifts parallel to or above and/or below the original drift excavations. For the latter multi-tier concept each 'tier' or 'level' would essentially replicate the original layer with a 30-m separation between tiers. This arrangement essentially doubles or triples the capacity of the repository for a two- or three-tier design, respectively. The main issues that affect the feasibility of expanded capacity design are; (i) ventilation requirements; (ii) radiation hazards; (iii) thermal and thermo-mechanical constraints. (i)Ventilation: The repository design involves waste packages mounted in close proximity to each other in 600-m long drifts that remain open and actively ventilated for at least 50-100 years. Analyses,conservatively assuming that all three repository levels operate simultaneously, indicate no technological obstacles in meeting ventilation requirements for sustained simultaneous operation ba sed on current industrial

Spanish ATLAS Tier-2: facing up to LHC Run 2

CERN Document Server

Gonzalez de la Hoz, Santiago; Fassi, Farida; Fernandez Casani, Alvaro; Kaci, Mohammed; Lacort Pellicer, Victor Ruben; Montiel Gonzalez, Almudena Del Rocio; Oliver Garcia, Elena; Pacheco Pages, Andres; Sánchez, Javier; Sanchez Martinez, Victoria; Salt, José; Villaplana Perez, Miguel

2015-01-01

The goal of this work is to describe the way of addressing the main challenges of Run-2 by the Spanish ATLAS Tier-2. The considerable increase of energy and luminosity for the upcoming Run-2 with respect to Run-1 has led to a revision of the ATLAS computing model as well as some of the main ATLAS computing tools. The adaptation on these changes will be shown, with the peculiarities that it is a distributed Tier-2 composed of three sites and its members are involved on ATLAS computing tasks with a hub of research, innovation and education.

Three Tier Unified Process Model for Requirement Negotiations and Stakeholder Collaborations

Science.gov (United States)

Niazi, Muhammad Ashraf Khan; Abbas, Muhammad; Shahzad, Muhammad

2012-11-01

This research paper is focused towards carrying out a pragmatic qualitative analysis of various models and approaches of requirements negotiations (a sub process of requirements management plan which is an output of scope managementís collect requirements process) and studies stakeholder collaborations methodologies (i.e. from within communication management knowledge area). Experiential analysis encompass two tiers; first tier refers to the weighted scoring model while second tier focuses on development of SWOT matrices on the basis of findings of weighted scoring model for selecting an appropriate requirements negotiation model. Finally the results are simulated with the help of statistical pie charts. On the basis of simulated results of prevalent models and approaches of negotiations, a unified approach for requirements negotiations and stakeholder collaborations is proposed where the collaboration methodologies are embeded into selected requirements negotiation model as internal parameters of the proposed process alongside some external required parameters like MBTI, opportunity analysis etc.

Nuclear power for coexistence with nature, high temperature gas-cooled reactors

International Nuclear Information System (INIS)

Kaneko, Yoshihiko

1996-01-01

Until this century, it is sufficient to aim at the winner of competition in human society to obtain resources, and to entrust waste to natural cleaning action. However, the expansion of social activities has been too fast, and the scale has become too large, consequently, in the next century, the expansion of social activities will be caught by the structure of trilemma that is subjected to the strong restraint and selection from the problems of finite energy and resources and environment preservation. In 21st century, the problems change to those between mankind and nature. Energy supply and population increase, envrionment preservation and human activities, and the matters that human wisdom should bear regarding energy technology are discussed. In Japan, the construction of the high temperature engineering test reactor (HTTR) is in progress. The design of high temperature gas-cooled reactors and their features on the safety are explained. The capability of reducing CO 2 release of high temperature gas-cooled reactors is reported. In future, it is expected that the time of introducing high temperature gas-cooled reactors will come. (K.I.)

Discussion on Design Transients of Pebble-bed High Temperature Gas-cooled Reactor

International Nuclear Information System (INIS)

Wang Yan; Li Fu; Zheng Yanhua

2014-01-01

In order to assure high quality for the components and their supports in the reactor coolant system, etc., some thermal-hydraulic transient conditions will be selected and researched for equipment design evaluation to satisfy the requirements ASME code, which are based on the conservative estimates of the magnitude and frequency of the temperature and pressure transients resulting from various operating conditions in the plant. In the mature design on pressurized water reactor, five conditions are considered. For the developing advanced pebble-bed high temperature gas-cooled reactor(HTGR), its design and operation has much difference with other reactors, so the transients of the pebble-bed high temperature gas-cooled reactor have distinctive characteristics. In this paper, the possible design transients of the pebble-bed HTGR will be discussed, and the frequency of design transients for equipment fatigue analysis and stress analysis due to cyclic stresses is also studied. The results will provide support for the design and construct of the pebble-bed HTGR. (author)

The High Flux Beam Reactor at Brookhaven National Laboratory

International Nuclear Information System (INIS)

Shapiro, S.M.

1994-01-01

Brookhaven National Laboratory's High Flux Beam Reactor (HFBR) was built because of the need of the scientist to always want 'more'. In the mid-50's the Brookhaven Graphite reactor was churning away producing a number of new results when the current generation of scientists, led by Donald Hughes, realized the need for a high flux reactor and started down the political, scientific and engineering path that led to the BFBR. The effort was joined by a number of engineers and scientists among them, Chemick, Hastings, Kouts, and Hendrie, who came up with the novel design of the HFBR. The two innovative features that have been incorporated in nearly all other research reactors built since are: (i) an under moderated core arrangement which enables the thermal flux to peak outside the core region where beam tubes can be placed, and (ii) beam tubes that are tangential to the core which decrease the fast neutron background without affecting the thermal beam intensity. Construction began in the fall of 1961 and four years later, at a cost of $12 Million, criticality was achieved on Halloween Night, 1965. Thus began 30 years of scientific accomplishments

Study on thermodynamic cycle of high temperature gas-cooled reactor

International Nuclear Information System (INIS)

Qu Xinhe; Yang Xiaoyong; Wang Jie

2017-01-01

The development trend of the (very) High temperature gas-cooled reactor is to gradually increase the reactor outlet temperature. The different power conversion units are required at the different reactor outlet temperature. In this paper, for the helium turbine direct cycle and the combined cycle of the power conversion unit of the High temperature gas-cooled reactor, the mathematic models are established, and three cycle plans are designed. The helium turbine direct cycle is a Brayton cycle with recuperator, precooler and intercooler. In the combined cycle plan 1, the topping cycle is a simple Brayton cycle without recuperator, precooler and intercooler, and the bottoming cycle is based on the steam parameters (540deg, 6 MPa) recommended by Siemens. In the combined cycle plan 2, the topping cycle also is a simple Brayton cycle, and the bottoming cycle which is a Rankine cycle with reheating cycle is based on the steam parameters of conventional subcritical thermal power generation (540degC, 18 MPa). The optimization results showed that the cycle efficiency of the combined cycle plan 2 is the highest, the second is the helium turbine direct cycle, and the combined cycle plan 2 is the lowest. When the reactor outlet temperature is 900degC and the pressure ratio is 2.02, the cycle efficiency of the combined cycle plan 2 can reach 49.7%. The helium turbine direct cycle has a reactor inlet temperature above 500degC due to the regenerating cycle, so it requires a cooling circuit for the internal wall of the reactor pressure vessel. When the reactor outlet temperature increases, the increase of the pressure ratio required by the helium turbine direct cycle increases may bring some difficulties to the design and manufacture of the magnetic bearings. For the combined cycle, the reactor inlet temperature can be controlled below than 370degC, so the reactor pressure vessel can use SA533 steel without cooling the internal wall of the reactor pressure vessel. The pressure

Plastic reactor suitable for high pressure and supercritical fluid electrochemistry

DEFF Research Database (Denmark)

Branch, Jack; Alibouri, Mehrdad; Cook, David A.

2017-01-01

The paper describes a reactor suitable for high pressure, particularly supercritical fluid, electrochemistry and electrodeposition at pressures up to 30 MPa at 115◦C. The reactor incorporates two key, new design concepts; a plastic reactor vessel and the use of o-ring sealed brittle electrodes...... by the deposition of Bi. The application of the reactor to the production of nanostructures is demonstrated by the electrodeposition of ∼80 nm diameter Te nanowires into an anodic alumina on silicon template. Key advantages of the new reactor design include reduction of the number of wetted materials, particularly...... glues used for insulating electrodes, compatability with reagents incompatible with steel, compatability with microfabricated planar multiple electrodes, small volume which brings safety advantages and reduced reagent useage, and a significant reduction in experimental time....

Modeling and Simulation of the Multi-module High Temperature Gas-cooled Reactor

International Nuclear Information System (INIS)

Liu Dan; Sun Jun; Sui Zhe; Xu Xiaolin; Ma Yuanle; Sun Yuliang

2014-01-01

The modular high temperature gas-cooled reactor (MHTGR) is characterized with the inherent safety. To enhance its economic benefit, the capital cost of MHTGR can be decreased by combining more reactor modules into one unit and realize the batch constructions in the concept of modularization. In the research and design of the multi-module reactors, one difficulty is to clarify the coupling effects of different modules in operating the reactors due to the shared feed water and main steam systems in the secondary loop. In the advantages of real-time simulation and coupling calculations of different modules and sub-systems, the operation of multi-module reactors can be studied and analyzed to understand the range and extent of the coupling effects. In the current paper; the engineering simulator for the multi-module reactors was realized and able to run in high performance computers, based on the research experience of the HTR-PM engineering simulator. The models were detailed introduced including the primary and secondary loops. The steady state of full power operation was demonstrated to show the good performance of six-module reactors. Typical dynamic processes, such as adjusting feed water flow rates and shutting down one reactor; were also tested to study the coupling effects in multi-module reactors. (author)

Assessing the nutritional quality of diets of Canadian children and adolescents using the 2014 Health Canada Surveillance Tool Tier System

OpenAIRE

Jessri, Mahsa; Nishi, Stephanie K.; L?Abbe, Mary R.

2016-01-01

Background Health Canada?s Surveillance Tool (HCST) Tier System was developed in 2014 with the aim of assessing the adherence of dietary intakes with Eating Well with Canada?s Food Guide (EWCFG). HCST uses a Tier system to categorize all foods into one of four Tiers based on thresholds for total fat, saturated fat, sodium, and sugar, with Tier 4 reflecting the unhealthiest and Tier 1 the healthiest foods. This study presents the first application of the HCST to examine (i) the dietary pattern...

Parametric study for high conversion pebble bed reactor

Energy Technology Data Exchange (ETDEWEB)

Teuchert, E.; Ruetten, H. J.

1975-06-15

Tables are presented of fuel cycle costs, conversion ratios and accompanying variations in fuel element designs for a 3,00 MWth high conversion pebble bed reactor with initial high enriched uranium/thorium cycle and subsequent recycling of U-233, Pu-239 and Pu-241.

RAPID-L Highly Automated Fast Reactor Concept Without Any Control Rods (1) Reactor concept and plant dynamics analyses

International Nuclear Information System (INIS)

Kambe, Mitsuru; Tsunoda, Hirokazu; Mishima, Kaichiro; Iwamura, Takamichi

2002-01-01

The 200 kWe uranium-nitride fueled lithium cooled fast reactor concept 'RAPID-L' to achieve highly automated reactor operation has been demonstrated. RAPID-L is designed for Lunar base power system. It is one of the variants of RAPID (Refueling by All Pins Integrated Design), fast reactor concept, which enable quick and simplified refueling. The essential feature of RAPID concept is that the reactor core consists of an integrated fuel assembly instead of conventional fuel subassemblies. In this small size reactor core, 2700 fuel pins are integrated altogether and encased in a fuel cartridge. Refueling is conducted by replacing a fuel cartridge. The reactor can be operated without refueling for up to 10 years. Unique challenges in reactivity control systems design have been attempted in RAPID-L concept. The reactor has no control rod, but involves the following innovative reactivity control systems: Lithium Expansion Modules (LEM) for inherent reactivity feedback, Lithium Injection Modules (LIM) for inherent ultimate shutdown, and Lithium Release Modules (LRM) for automated reactor startup. All these systems adopt lithium-6 as a liquid poison instead of B 4 C rods. In combination with LEMs, LIMs and LRMs, RAPID-L can be operated without operator. This is the first reactor concept ever established in the world. This reactor concept is also applicable to the terrestrial fast reactors. In this paper, RAPID-L reactor concept and its transient characteristics are presented. (authors)

High-burn-up fuels for fast reactors. Past experience and novel applications

International Nuclear Information System (INIS)

Weaver, Kevan D.; Gilleland, John; Whitmer, Charles; Zimmerman, George

2009-01-01

Fast reactors in the U.S. routinely achieved fuel burn-ups of 10%, with some fuel able to reach peak burn-ups of 20%, notably in the Experimental Breeder Reactor II and the Fast Flux Test Facility. Maximum burn-up has historically been constrained by chemical and mechanical interactions between the fuel and its cladding, and to some extent by radiation damage and thermal effects (e.g., radiation-induced creep, thermal creep, and radiation embrittlement) that cause the cladding to weaken. Although fast reactors have used several kinds of fuel - including oxide, metal alloy, carbide, and nitride - the vast majority of experience with fast reactors has been using oxide (including mixed oxide) and metal-alloy fuels based on uranium. Our understanding of high-burn-up operation is also limited by the fact that breeder reactor programs have historically assumed that their fuel would eventually undergo reprocessing; the programs thus have not made high burn-up a top priority. Recently a set of novel designs have emerged for fast reactors that require little initial enrichment and no reprocessing. These reactors exploit a concept known as a traveling wave (sometimes referred to as a breed-and-burn wave, fission wave, or nuclear-burning wave). By breeding and using its own fuel in place as it operates, a traveling-wave reactor can obtain burn-ups that approach 50%, well beyond the current base of knowledge and experience. Our computational work on the physics of traveling-wave reactors shows that they require metal-alloy fuel to provide the margins of reactivity necessary to sustain a breed-and-burn wave. This paper reviews operating experience with high-burn-up fuels and the technical feasibility of moving to a qualitatively new burn-up regime. We discuss our calculations on traveling-wave reactors, including those concerning the possible use of thorium. The challenges associated with high burn-up and fluence in fuels and materials are also discussed. (author)

An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions

International Nuclear Information System (INIS)

Ruan, Guihua; Wu, Zhenwei; Huang, Yipeng; Wei, Meiping; Su, Rihui; Du, Fuyou

2016-01-01

A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of N_α-benzoyl-L-arginine ethyl ester to N_α-benzoyl-L-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast and easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas. - Graphical abstract: Schematic illustration of preparation of hypercrosslinking polyHIPE immobilized enzyme reactor for on-column protein digestion. - Highlights: • A reactor was prepared and used for enzyme immobilization and continuous on-column protein digestion. • The new polyHIPE IMER was quite suit for protein digestion with good properties. • On-column digestion revealed that the IMER was easy regenerated by HCl without any structure destruction.

An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions

Energy Technology Data Exchange (ETDEWEB)

Ruan, Guihua, E-mail: guihuaruan@hotmail.com [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004 (China); Wu, Zhenwei; Huang, Yipeng; Wei, Meiping; Su, Rihui [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Du, Fuyou, E-mail: dufu2005@126.com [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004 (China)

2016-04-22

A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of N{sub α}-benzoyl-L-arginine ethyl ester to N{sub α}-benzoyl-L-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast and easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas. - Graphical abstract: Schematic illustration of preparation of hypercrosslinking polyHIPE immobilized enzyme reactor for on-column protein digestion. - Highlights: • A reactor was prepared and used for enzyme immobilization and continuous on-column protein digestion. • The new polyHIPE IMER was quite suit for protein digestion with good properties. • On-column digestion revealed that the IMER was easy regenerated by HCl without any structure destruction.

Fuel-Cycle and Nuclear Material Disposition Issues Associated with High-Temperature Gas Reactors

International Nuclear Information System (INIS)

Shropshire, D.E.; Herring, J.S.

2004-01-01

The objective of this paper is to facilitate a better understanding of the fuel-cycle and nuclear material disposition issues associated with high-temperature gas reactors (HTGRs). This paper reviews the nuclear fuel cycles supporting early and present day gas reactors, and identifies challenges for the advanced fuel cycles and waste management systems supporting the next generation of HTGRs, including the Very High Temperature Reactor, which is under development in the Generation IV Program. The earliest gas-cooled reactors were the carbon dioxide (CO2)-cooled reactors. Historical experience is available from over 1,000 reactor-years of operation from 52 electricity-generating, CO2-cooled reactor plants that were placed in operation worldwide. Following the CO2 reactor development, seven HTGR plants were built and operated. The HTGR came about from the combination of helium coolant and graphite moderator. Helium was used instead of air or CO2 as the coolant. The helium gas has a significant technical base due to the experience gained in the United States from the 40-MWe Peach Bottom and 330-MWe Fort St. Vrain reactors designed by General Atomics. Germany also built and operated the 15-MWe Arbeitsgemeinschaft Versuchsreaktor (AVR) and the 300-MWe Thorium High-Temperature Reactor (THTR) power plants. The AVR, THTR, Peach Bottom and Fort St. Vrain all used fuel containing thorium in various forms (i.e., carbides, oxides, thorium particles) and mixtures with highly enriched uranium. The operational experience gained from these early gas reactors can be applied to the next generation of nuclear power systems. HTGR systems are being developed in South Africa, China, Japan, the United States, and Russia. Elements of the HTGR system evaluated included fuel demands on uranium ore mining and milling, conversion, enrichment services, and fuel fabrication; fuel management in-core; spent fuel characteristics affecting fuel recycling and refabrication, fuel handling, interim

High-temperature reactors: a recent past, a near future

International Nuclear Information System (INIS)

Ballot, B.

2007-01-01

While high-temperature reactors did experience major developments in the past, in Europe in particular, significant R and D efforts are required, if a major innovation deployment is to be made possible, of modular reactors having the capability of being coupled, in reliable, economic fashion, to an industrial process. The aim: the construction, before the next decade is out more swiftly than is feasible for other fourth-generation systems of an industrial prototype, coupled to such a process. The Areva Group takes up this approach, with its ANTARES project. For the purposes of characterizing the thermal properties of heterogeneous, multi-scale materials, as a function of temperature, experimental and numerical instruments have been developed at the Microstructure and Behavior Laboratory (Laboratoire microstructure et comportement), at CEA Le Ripault Center. They have been applied to the thermal characterization of the various layers in a high temperature reactor (HTR) fuel ball. (authors)

The need for high performance breeder reactors

International Nuclear Information System (INIS)

Vaughan, R.D.; Chermanne, J.

1977-01-01

It can be easily demonstrated, on the basis of realistic estimates of continued high oil costs, that an increasing portion of the growth in energy demand must be supplied by nuclear power and that this one might account for 20% of all the energy production by the end of the century. Such assumptions lead very quickly to the conclusion that the discovery, extraction and processing of the uranium will not be able to follow the demand; the bottleneck will essentially be related to the rate at which the ore can be discovered and extracted, and not to the existing quantities nor their grade. Figures as high as 150.000 T/annum and more would be quickly reached, and it is necessary to wonder already now if enough capital can be attracted to meet these requirements. There is only one solution to this problem: improve the conversion ratio of the nuclear system and quickly reach the breeding; this would lead to the reduction of the natural uranium consumption by a factor of about 50. However, this condition is not sufficient; the commercial breeder must have a breeding gain as high as possible because the Pu out-of-pile time and the Pu losses in the cycle could lead to an unacceptable doubling time for the system, if the breeding gain is too low. That is the reason why it is vital to develop high performance breeder reactors. The present paper indicates how the Gas-cooled Breeder Reactor [GBR] can meet the problems mentioned above, on the basis of recent and realistic studies. It briefly describes the present status of GBR development, from the predecessors in the gas cooled reactor line, particularly the AGR. It shows how the GBR fuel takes mostly profit from the LMFBR fuel irradiation experience. It compares the GBR performance on a consistent basis with that of the LMFBR. The GBR capital and fuel cycle costs are compared with those of thermal and fast reactors respectively. The conclusion is, based on a cost-benefit study, that the GBR must be quickly developed in order

A retrospective tiered environmental assessment of the Mount Storm Wind Energy Facility, West Virginia,USA

Energy Technology Data Exchange (ETDEWEB)

Efroymson, Rebecca Ann [ORNL; Day, Robin [No Affiliation; Strickland, M. Dale [Western EcoSystems Technology

2012-11-01

Bird and bat fatalities from wind energy projects are an environmental and public concern, with post-construction fatalities sometimes differing from predictions. Siting facilities in this context can be a challenge. In March 2012 the U.S. Fish and Wildlife Service (USFWS) released Land-based Wind Energy Guidelines to assess collision fatalities and other potential impacts to species of concern and their habitats to aid in siting and management. The Guidelines recommend a tiered approach for assessing risk to wildlife, including a preliminary site evaluation that may evaluate alternative sites, a site characterization, field studies to document wildlife and habitat and to predict project impacts, post construction studies to estimate impacts, and other post construction studies. We applied the tiered assessment framework to a case study site, the Mount Storm Wind Energy Facility in Grant County, West Virginia, USA, to demonstrate the use of the USFWS assessment approach, to indicate how the use of a tiered assessment framework might have altered outputs of wildlife assessments previously undertaken for the case study site, and to assess benefits of a tiered ecological assessment framework for siting wind energy facilities. The conclusions of this tiered assessment for birds are similar to those of previous environmental assessments for Mount Storm. This assessment found risk to individual migratory tree-roosting bats that was not emphasized in previous preconstruction assessments. Differences compared to previous environmental assessments are more related to knowledge accrued in the past 10 years rather than to the tiered structure of the Guidelines. Benefits of the tiered assessment framework include good communication among stakeholders, clear decision points, a standard assessment trajectory, narrowing the list of species of concern, improving study protocols, promoting consideration of population-level effects, promoting adaptive management through post

MYRRHA a multi-purpose hybrid research reactor for high-tech applications

International Nuclear Information System (INIS)

Abderrahim, H. A.; Baeten, P.

2012-01-01

MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) is the flexible experimental accelerator driven system (ADS) in development at SCK-CEN. MYRRHA is able to work both in subcritical (ADS) as in critical mode. In this way, MYRRHA will allow fuel developments for innovative reactor systems, material developments for generation IV (GEN IV) systems, material developments for fusion reactors, radioisotope production and industrial applications, such as Si-doping. MYRRHA will also demonstrate the ADS full concept by coupling the three components (accelerator, spallation target and subcritical reactor) at reasonable power level to allow operation feedback, scalable to an industrial demonstrator and allow the study of efficient transmutation of high-level nuclear waste. MYRRHA is based on the heavy liquid metal technology and so it will contribute to the development of lead fast reactor (LFR) technology and in critical mode, MYRRHA will play the role of European technology pilot plant in the roadmap for LFR. In this paper the historical evolution of MYRRHA and the rationale behind the design choices is presented and the latest configuration of the reactor core and primary system is described. (authors)

Sustainability and Efficiency Improvements of Gas-Cooled High Temperature Reactors

International Nuclear Information System (INIS)

Marmier, Alain

2012-01-01

This thesis covers 3 fundamental aspects of High Temperature Reactor (HTR) performance: fuel testing under irradiation for maximized safety and sustainability, fuel architecture for improved economy and sustainability, and a novel Balance of Plant concept to enable future high-tech process heat applications with minimized R and D. The HTR concept features important inherent and passive safety characteristics: high thermal inertia and good thermal conductivity of the core; a negative Doppler coefficient; high quality of fuel elements and low power density. These features keep the core temperature within safe boundaries and minimise fission product release, even in case of severe accidents. The Very High Temperature reactor (VHTR) is based on the same safety concept as the initial HTR, but it aims at offering better economy with a higher reactor outlet temperature (and thus efficiency) and a high fuel discharge burn-up (and thus better sustainability). The inherent safety features of HTR have been demonstrated in small pebble-bed reactors in practice, but have to be replicated for reactors with industrially relevant size and power. An increase of the power density (in order to increase the helium coolant outlet temperature) leads to higher fuel temperatures and therefore higher fuel failure probability. The core of a pebble-bed reactor consists of 6 cm diameter spheres (pebbles) that form a randomly packed porous bed, which is cooled by high pressure helium. These pebbles contain thousands of 1 mm diameter fuel particles baked into a graphite matrix. These fuel particles, in turn, consist of a fuel kernel with successive coatings of pyrocarbon and silicon carbide layers. The coating layers are designed to contain the fission products that build up during operation of the reactor. The feasibility and performance of the fuel requires experimental verification in view of fuel qualification and licensing. For HTR fuel, the required test string comprises amongst others

Thermal hydraulics analysis of the Advanced High Temperature Reactor

Energy Technology Data Exchange (ETDEWEB)

Wang, Dean, E-mail: Dean_Wang@uml.edu [University of Massachusetts Lowell, One University Avenue, Lowell, MA 01854 (United States); Yoder, Graydon L.; Pointer, David W.; Holcomb, David E. [Oak Ridge National Laboratory, 1 Bethel Valley RD #6167, Oak Ridge, TN 37831 (United States)

2015-12-01

Highlights: • The TRACE AHTR model was developed and used to define and size the DRACS and the PHX. • A LOFF transient was simulated to evaluate the reactor performance during the transient. • Some recommendations for modifying FHR reactor system component designs are discussed. - Abstract: The Advanced High Temperature Reactor (AHTR) is a liquid salt-cooled nuclear reactor design concept, featuring low-pressure molten fluoride salt coolant, a carbon composite fuel form with embedded coated particle fuel, passively triggered negative reactivity insertion mechanisms, and fully passive decay heat rejection. This paper describes an AHTR system model developed using the Nuclear Regulatory Commission (NRC) thermal hydraulic transient code TRAC/RELAP Advanced Computational Engine (TRACE). The TRACE model includes all of the primary components: the core, downcomer, hot legs, cold legs, pumps, direct reactor auxiliary cooling system (DRACS), the primary heat exchangers (PHXs), etc. The TRACE model was used to help define and size systems such as the DRACS and the PHX. A loss of flow transient was also simulated to evaluate the performance of the reactor during an anticipated transient event. Some initial recommendations for modifying system component designs are also discussed. The TRACE model will be used as the basis for developing more detailed designs and ultimately will be used to perform transient safety analysis for the reactor.

Safety philosophy of gas turbine high temperature reactor (GTHTR300)

International Nuclear Information System (INIS)

Shoji Katanishi; Kazuhiko Kunitomi; Shusaku Shiozawa

2002-01-01

Japan Atomic Energy Research Institute (JAERI) has undertaken the study of an original design concept of gas turbine high temperature reactor, the GTHTR300. The general concept of this study is development of a greatly simplified design that leads to substantially reduced technical and cost requirements. Newly proposed design features enable the GTHTR300 to be an efficient and economically competitive reactor in 2010's. Also, the GTHTR300 fully takes advantage of its inherent safety characteristics. The safety philosophy of the GTHTR300 is developed based on the HTTR (High Temperature Engineering Test Reactor) of JAERI which is the first HTGR in Japan. Major features of the newly proposed safety philosophy for the GTHTR300 are described in this article. (authors)

Very High Efficiency Reactor (VHER) Concepts for Electrical Power Generation and Hydrogen Production

International Nuclear Information System (INIS)

PARMA JR, EDWARD J.; PICKARD, PAUL S.; SUO-ANTTILA, AHTI JORMA

2003-01-01

The goal of the Very High Efficiency Reactor study was to develop and analyze concepts for the next generation of nuclear power reactors. The next generation power reactor should be cost effective compared to current power generation plant, passively safe, and proliferation-resistant. High-temperature reactor systems allow higher electrical generating efficiencies and high-temperature process heat applications, such as thermo-chemical hydrogen production. The study focused on three concepts; one using molten salt coolant with a prismatic fuel-element geometry, the other two using high-pressure helium coolant with a prismatic fuel-element geometry and a fuel-pebble element design. Peak operating temperatures, passive-safety, decay heat removal, criticality, burnup, reactivity coefficients, and material issues were analyzed to determine the technical feasibility of each concept

High-temperature-structural design and research and development for reactor system components

International Nuclear Information System (INIS)

Matsumura, Makoto; Hada, Mikio

1985-01-01

The design of reactor system components requires high-temperature-structural design guide with the consideration of the creep effect of materials related to research and development on structural design. The high-temperature-structural design guideline for the fast prototype reactor MONJU has been developed under the active leadership by Power Reactor and Nuclear Fuel Development Corporation and Toshiba has actively participated to this work with responsibility on in-vessel components, performing research and development programs. This paper reports the current status of high-temperature-structural-design-oriented research and development programs and development of analytical system including stress-evaluation program. (author)

Safety analysis of the experimental multi-purpose high-temperature gas-cooled reactor

International Nuclear Information System (INIS)

Mitake, Susumu; Ezaki, Masahiro; Suzuki, Katsuo; Takaya, Junichi; Shimazu, Akira

1976-02-01

Safety features of the experimental multi-purpose high-temperature gas-cooled reactor being developed in JAERI were studied or the basis of its preliminary conceptual design of the reactor plant. Covered are control of the plant in transients, plant behaviour in accidents, and functions of engineered safeguards, and also dynamics of the uprant and frequencies of the accidents. These studies have shown, (i) the reactor plant can be operated both in plant slave to reactor and reactor slave to plant control, (ii) stable control of

High Flux Isotope Reactor (HFIR)

Data.gov (United States)

Federal Laboratory Consortium — The HFIR at Oak Ridge National Laboratory is a light-water cooled and moderated reactor that is the United States’ highest flux reactor-based neutron source. HFIR...

Use of thorium for high temperature gas-cooled reactors

Energy Technology Data Exchange (ETDEWEB)

Guimarães, Cláudio Q., E-mail: claudio_guimaraes@usp.br [Universidade de São Paulo (USP), SP (Brazil). Instituto de Física; Stefani, Giovanni L. de, E-mail: giovanni.stefani@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Santos, Thiago A. dos, E-mail: thiago.santos@ufabc.edu.br [Universidade Federal do ABC (UFABC), Santo André, SP (Brazil)

2017-07-01

The HTGR ( High Temperature Gas-cooled Reactor) is a 4{sup th} generation nuclear reactor and is fuelled by a mixture of graphite and fuel-bearing microspheres. There are two competitive designs of this reactor type: The German “pebble bed” mode, which is a system that uses spherical fuel elements, containing a graphite-and-fuel mixture coated in a graphite shell; and the American version, whose fuel is loaded into precisely located graphite hexagonal prisms that interlock to create the core of the vessel. In both variants, the coolant consists of helium pressurised. The HTGR system operates most efficiently with the thorium fuel cycle, however, so relatively little development has been carried out in this country on that cycle for HTGRs. In the Nuclear Engineering Centre of IPEN (Instituto de Pesquisas Energéticas e Nucleares), a study group is being formed linked to thorium reactors, whose proposal is to investigate reactors using thorium for {sup 233}U production and rejects burning. The present work intends to show the use of thorium in HTGRs, their advantages and disadvantages and its feasibility. (author)

Teaching Borges's "Garden": A Three-Tiered Approach.

Science.gov (United States)

Christensen, Maggie

2002-01-01

Describes how "The Garden of Forking Paths" presents teaching challenges that ultimately yield benefits worth the effort for students and instructors. Discusses a three-tiered approach: spy story, family history and character, and ideas of time and timelessness. Concludes that the three layers provide a structure to get the discussion started and…

Research and development for high temperature gas cooled reactor in Japan

International Nuclear Information System (INIS)

Taketani, K.

1978-01-01

The paper describes the current status of High Temperature Gas Cooled Reactor research and development work in Japan, with emphasis on the Experimental Very High Temperature Reactor (Exp. VHTR) to be built by Japan Atomic Energy Research Institute (JAERI) before the end of 1985. The necessity of construction of Exp. VHTR was explained from the points of Japanese energy problems and resources

Status report on high fidelity reactor simulation

International Nuclear Information System (INIS)

Palmiotti, G.; Smith, M.; Rabiti, C.; Lewis, E.; Yang, W.; Leclere, M.; Siegel, A.; Fischer, P.; Kaushik, D.; Ragusa, J.; Lottes, J.; Smith, B.

2006-01-01

This report presents the effort under way at Argonne National Laboratory toward a comprehensive, integrated computational tool intended mainly for the high-fidelity simulation of sodium-cooled fast reactors. The main activities carried out involved neutronics, thermal hydraulics, coupling strategies, software architecture, and high-performance computing. A new neutronics code, UNIC, is being developed. The first phase involves the application of a spherical harmonics method to a general, unstructured three-dimensional mesh. The method also has been interfaced with a method of characteristics. The spherical harmonics equations were implemented in a stand-alone code that was then used to solve several benchmark problems. For thermal hydraulics, a computational fluid dynamics code called Nek5000, developed in the Mathematics and Computer Science Division for coupled hydrodynamics and heat transfer, has been applied to a single-pin, periodic cell in the wire-wrap geometry typical of advanced burner reactors. Numerical strategies for multiphysics coupling have been considered and higher-accuracy efficient methods proposed to finely simulate coupled neutronic/thermal-hydraulic reactor transients. Initial steps have been taken in order to couple UNIC and Nek5000, and simplified problems have been defined and solved for testing. Furthermore, we have begun developing a lightweight computational framework, based in part on carefully selected open source tools, to nonobtrusively and efficiently integrate the individual physics modules into a unified simulation tool

Performance analysis of coordination strategies in two-tier Heterogeneous Networks

KAUST Repository

Boukhedimi, Ikram; Kammoun, Abla; Alouini, Mohamed-Slim

2016-01-01

Large scale multi-tier Heterogeneous Networks (HetNets) are expected to ensure a consistent quality of service (QoS) in 5G systems. Such networks consist of a macro base station (BS) equipped with a large number of antennas and a dense overlay of small cells. The small cells could be deployed within the same coverage of the macro-cell BS, thereby causing high levels of inter-cell interference. In this regard, coordinated beamforming techniques are considered as a viable solution to counteract the arising interference. The goal of this work is to analyze the efficiency of coordinated beamforming techniques in mitigating both intra-cell and inter-cell interference. In particular, we consider the downlink of a Time-division duplexing (TDD) massive multiple-input-multiple-output (MIMO) tier-HetNet and analyze different beamforming schemes together with different degrees of coordination between the BSs. We exploit random matrix theory tools in order to provide, in explicit form, deterministic equivalents for the average achievable rates in the macro-cell and the micro-cells. We prove that our theoretical derivations allow us to draw some conclusions regarding the role played by coordination strategies in reducing the inter-cell interference. These findings are finally validated by a selection of some numerical results. © 2016 IEEE.

Performance analysis of coordination strategies in two-tier Heterogeneous Networks

KAUST Repository

Boukhedimi, Ikram

2016-08-11

Large scale multi-tier Heterogeneous Networks (HetNets) are expected to ensure a consistent quality of service (QoS) in 5G systems. Such networks consist of a macro base station (BS) equipped with a large number of antennas and a dense overlay of small cells. The small cells could be deployed within the same coverage of the macro-cell BS, thereby causing high levels of inter-cell interference. In this regard, coordinated beamforming techniques are considered as a viable solution to counteract the arising interference. The goal of this work is to analyze the efficiency of coordinated beamforming techniques in mitigating both intra-cell and inter-cell interference. In particular, we consider the downlink of a Time-division duplexing (TDD) massive multiple-input-multiple-output (MIMO) tier-HetNet and analyze different beamforming schemes together with different degrees of coordination between the BSs. We exploit random matrix theory tools in order to provide, in explicit form, deterministic equivalents for the average achievable rates in the macro-cell and the micro-cells. We prove that our theoretical derivations allow us to draw some conclusions regarding the role played by coordination strategies in reducing the inter-cell interference. These findings are finally validated by a selection of some numerical results. © 2016 IEEE.

Technical aspects of high converter reactors

International Nuclear Information System (INIS)

1992-02-01

The meeting provided an opportunity to review and discuss national R and D programs, various technical aspects of and worldwide progress in the implementation of high conversion reactors. The meeting was attended by 66 participants from 18 countries and 2 international organizations. 33 papers were presented. A separate abstract was prepared for each of these papers. Refs, figs, tabs, slides and diagram

High-temperature Gas Reactor (HTGR)

Science.gov (United States)

Abedi, Sajad

2011-05-01

General Atomics (GA) has over 35 years experience in prismatic block High-temperature Gas Reactor (HTGR) technology design. During this period, the design has recently involved into a modular have been performed to demonstrate its versatility. This versatility is directly related to refractory TRISO coated - particle fuel that can contain any type of fuel. This paper summarized GA's fuel cycle studies individually and compares each based upon its cycle sustainability, proliferation-resistance capabilities, and other performance data against pressurized water reactor (PWR) fuel cycle data. Fuel cycle studies LEU-NV;commercial HEU-Th;commercial LEU-Th;weapons-grade plutonium consumption; and burning of LWR waste including plutonium and minor actinides in the MHR. results show that all commercial MHR options, with the exception of HEU-TH, are more sustainable than a PWR fuel cycle. With LEU-NV being the most sustainable commercial options. In addition, all commercial MHR options out perform the PWR with regards to its proliferation-resistance, with thorium fuel cycle having the best proliferation-resistance characteristics.

The JINR Tier1 Site Simulation for Research and Development Purposes

Directory of Open Access Journals (Sweden)

Korenkov V.

2016-01-01

A system for grid and cloud services simulation is developed at LIT (JINR, Dubna. This simulation system is focused on improving the effciency of the grid/cloud structures development by using the work quality indicators of some real system. The development of such kind of software is very important for making a new grid/cloud infrastructure for such big scientific experiments like the JINR Tier1 site for WLCG. The simulation of some processes of the Tier1 site is considered as an example of our application approach.

Tier One Performance Screen Initial Operational Test and Evaluation: 2014 Annual Report

Science.gov (United States)

2017-07-01

tier reported in the current report differ from corresponding figures in previous reports. The differences are generally minor and do not impact the...decisions quickly; they see themselves (and they may be perceived by others) as knowledgeable, astute, or intellectual. Non- Delinquency High scoring...08 1.00 Even Tempered .01 .98 .00 .98 .15 .99 Intellectual Efficiency -.02 .97 -.02 .98 .10 .95 Non- Delinquency .03 .98 .04 .98 -.06 1.02

Physics of high-temperature reactors

International Nuclear Information System (INIS)

Massimo, L.

1976-01-01

The subject is covered in chapters entitled: general description of the HTR core; general considerations about reactor physics; neutron cross-sections; basic aspects of transport and diffusion theory; methods for the solution of the diffusion equation; slowing-down and thermalization in graphite; resonance absorption; spectrum calculations and cross-section averaging; burn-up; core design; fuel management and cost calculations; temperature coefficient; core dynamics and accident analysis; reactor control; peculiarities of HTR physics; analysis of calculational accuracy; sequence of reactor design calculations. (U.K.)

Generation IV reactors: reactor concepts

International Nuclear Information System (INIS)

Cardonnier, J.L.; Dumaz, P.; Antoni, O.; Arnoux, P.; Bergeron, A.; Renault, C.; Rimpault, G.; Delpech, M.; Garnier, J.C.; Anzieu, P.; Francois, G.; Lecomte, M.

2003-01-01

Liquid metal reactor concept looks promising because of its hard neutron spectrum. Sodium reactors benefit a large feedback experience in Japan and in France. Lead reactors have serious assets concerning safety but they require a great effort in technological research to overcome the corrosion issue and they lack a leader country to develop this innovative technology. In molten salt reactor concept, salt is both the nuclear fuel and the coolant fluid. The high exit temperature of the primary salt (700 Celsius degrees) allows a high energy efficiency (44%). Furthermore molten salts have interesting specificities concerning the transmutation of actinides: they are almost insensitive to irradiation damage, some salts can dissolve large quantities of actinides and they are compatible with most reprocessing processes based on pyro-chemistry. Supercritical water reactor concept is based on operating temperature and pressure conditions that infers water to be beyond its critical point. In this range water gets some useful characteristics: - boiling crisis is no more possible because liquid and vapour phase can not coexist, - a high heat transfer coefficient due to the low thermal conductivity of supercritical water, and - a high global energy efficiency due to the high temperature of water. Gas-cooled fast reactors combining hard neutron spectrum and closed fuel cycle open the way to a high valorization of natural uranium while minimizing ultimate radioactive wastes and proliferation risks. Very high temperature gas-cooled reactor concept is developed in the prospect of producing hydrogen from no-fossil fuels in large scale. This use implies a reactor producing helium over 1000 Celsius degrees. (A.C.)

Assessment of very high temperature reactors in process applications

International Nuclear Information System (INIS)

Jones, J.E. Jr.; Spiewak, I.; Gambill, W.R.

1976-01-01

In April 1974, the United States Energy Research and Development Administration (ERDA) authorized General Atomic Company, General Electric Company, and Westinghouse Astronuclear Laboratory to assess the available technology for producing process heat utilizing a very high temperature nuclear reactor (VHTR). The VHTR is defined as a gas-cooled graphite-moderated reactor. Oak Ridge National Laboratory has been given a lead role in evaluating the VHTR reactor studies and potential applications of the VHTR. Process temperatures up to the 760 to 871 0 C range appear to be achievable with near-term technology. The major development considerations are high temperature materials, the safety questions (especially regarding the need for an intermediate heat exchanger) and the process heat exchanger. The potential advantages of the VHTR over competing fossil energy sources are conservation of fossil fuels and reduced atmospheric impacts. Costs are developed for nuclear process heat supplied from a 3000-MW(th) VHTR. The range of cost in process applications is competitive with current fossil fuel alternatives

Development of the design of the High Temperature Gas Cooled Reactor experiment

International Nuclear Information System (INIS)

Lockett, G.E.; Huddle, R.A.U.

1960-01-01

Early in 1956 a small team was formed at the Atomic Energy Research Establishment, Harwell, to investigate the possibilities of the High Temperature Gas Cooled (H.T.G.C.) Reactor System. Although the primary objective of this team was to carry out a feasibility study of the system as a whole, it soon became apparent that, in addition to design studies and economic surveys of power producing reactors, the most appropriate approach to such a novel system was to carry out a design study of a relatively small (10 to 20 M.W.) Reactor Experiment, together with the necessary research and development work associated with such a reactor. This work proceeded within the U.K.A.E.A. during the three following years, and it was felt that realistic design proposals could be put forward with sufficient confidence to justify the detailed design and construction of a 20 M.W. Reactor Experiment. In April 1959 responsibility for this Reactor Experiment was taken over by the O.E.E.C. High Temperature Gas Cooled Reactor Project, the DRAGON Project, at the Atomic Energy Establishment, Winfrith, Dorset. In this Paper the research, development, and design work is reviewed, and the proposals for the Reactor Experiment are summarised. (author)

An algal model for predicting attainment of tiered biological criteria of Maine's streams and rivers

Science.gov (United States)

Danielson, Thomas J.; Loftin, Cyndy; Tsomides, Leonidas; DiFranco, Jeanne L.; Connors, Beth; Courtemanch, David L.; Drummond, Francis; Davies, Susan

2012-01-01

State water-quality professionals developing new biological assessment methods often have difficulty relating assessment results to narrative criteria in water-quality standards. An alternative to selecting index thresholds arbitrarily is to include the Biological Condition Gradient (BCG) in the development of the assessment method. The BCG describes tiers of biological community condition to help identify and communicate the position of a water body along a gradient of water quality ranging from natural to degraded. Although originally developed for fish and macroinvertebrate communities of streams and rivers, the BCG is easily adapted to other habitats and taxonomic groups. We developed a discriminant analysis model with stream algal data to predict attainment of tiered aquatic-life uses in Maine's water-quality standards. We modified the BCG framework for Maine stream algae, related the BCG tiers to Maine's tiered aquatic-life uses, and identified appropriate algal metrics for describing BCG tiers. Using a modified Delphi method, 5 aquatic biologists independently evaluated algal community metrics for 230 samples from streams and rivers across the state and assigned a BCG tier (1–6) and Maine water quality class (AA/A, B, C, nonattainment of any class) to each sample. We used minimally disturbed reference sites to approximate natural conditions (Tier 1). Biologist class assignments were unanimous for 53% of samples, and 42% of samples differed by 1 class. The biologists debated and developed consensus class assignments. A linear discriminant model built to replicate a priori class assignments correctly classified 95% of 150 samples in the model training set and 91% of 80 samples in the model validation set. Locally derived metrics based on BCG taxon tolerance groupings (e.g., sensitive, intermediate, tolerant) were more effective than were metrics developed in other regions. Adding the algal discriminant model to Maine's existing macroinvertebrate discriminant

Fundamentalists, Priests, Martyrs and Converts: A Typology of First Tier Management in Further Education

Science.gov (United States)

Page, Damien

2011-01-01

This article presents findings from a study of first tier managers in English Further Education colleges, a role critically neglected within the literature, despite its centrality to organisational effectiveness and learner success. The role was found to be diverse, contested and elastic and while first tier managers were found to be highly…

How two-tier boards can be more effective

NARCIS (Netherlands)

dr. Stefan Peij; Pieter-Jan Bezemer; Laura de Kruijs; Gregory Maassen

2014-01-01

Purpose – This study seeks to explore how non-executive directors address governance problems on Dutch two-tier boards. Within this board model, challenges might be particularly difficult to address due to the formal separation of management boards' decision-management from supervisory boards'

76 FR 79221 - Penske Logistics, LLC, Customer Service Department General Motors and Tier Finished Goods...

Science.gov (United States)

2011-12-21

..., Customer Service Department General Motors and Tier Finished Goods/Finished Goods Division; a Subsidiary of... Manpower El Paso, TX; Amended Certification Regarding Eligibility To Apply for Worker Adjustment Assistance... should read Penske Logistics, LLC, Customer Service Department, General Motors and Tier Finished Goods...

High-temperature reactor developments in the Netherlands

International Nuclear Information System (INIS)

Schram, R.P.C.; Cordfunke, E.H.P.; Heek, A.I. van

1996-01-01

The high-temperature reactor development in the Netherlands is embedded in the WHITE reactor program, in which several Dutch research institutes and engineering companies participate. The activities within the WHITE program are focused on the development of a small scale HTR for combined heat and power generation. In 1995, design choices for a pebble bed reactor were made at ECN. The first concept HTR will have a closed cycle helium turbine and a power level of 40 MWth. It is intended to make the market introduction of a commercially competitive HTR feasible. As a part of the HTR program at ECN, chemical aspects of HTR fuel and coated particles are studied. Experimental work on the oxidation resistance of coating materials and fission product attack on coating materials as well as thermochemical calculations of the fuel particles are done at ECN. The concept-HTR of ECN is fuelled with UO 2 , but the use of thorium is considered. The composition of the fuel determines the oxygen potential, which plays a key role in chemical safety of the fuel. Thermochemical calculations of the chemical form of cesium inside the HTR fuel particles were performed for a wide oxygen potential range. The chemical form of cesium determines the cesium pressure inside the fuel particle, which in turn determines the release behavior of Cs from defective particles. At normal operating temperatures and low oxygen potentials, the chemical form of cesium is C 60 Cs. It is known that cesium carbon compounds decompose above 650degC in vacuum. The stability of these compounds in the fuel particles at high temperatures(1000-1600degC) is questioned. Decomposition of these compounds may result in high cesium pressures even at normal operating conditions. Experimental work on the thermodynamic properties of cesium compounds at high temperatures is currently performed. (J.P.N.)

Very high flux steady state reactor and accelerator based sources

International Nuclear Information System (INIS)

Ludewig, H.; Todosow, M.; Simos, N.; Shapiro, S.; Hastings, J.

2004-01-01

With the number of steady state neutron sources in the US declining (including the demise of the Bnl HFBR) the remaining intense sources are now in Europe (i.e. reactors - ILL and FMR, accelerator - PSI). The intensity of the undisturbed thermal flux for sources currently in operation ranges from 10 14 n/cm 2 *s to 10 15 n/cm 2 *s. The proposed Advanced Neutron Source (ANS) was to be a high power reactor (about 350 MW) with a projected undisturbed thermal flux of 7*10 15 n/cm 2 *s but never materialized. The objective of the current study is to explore the requirements and implications of two source concepts with an undisturbed flux of 10 16 n/cm 2 *s. The first is a reactor based concept operating at high power density (10 MW/l - 15 MW/l) and a total power of 100 MW - 250 MW, depending on fissile enrichment. The second is an accelerator based concept relying on a 1 GeV - 1.5 GeV proton Linac with a total beam power of 40 MW and a liquid lead-bismuth eutectic target. In the reactor source study, the effects of fissile material enrichment, coolant temperature and pressure drop, and estimates of pressure vessel stress levels will be investigated. The fuel form for the reactor will be different from all other operating source reactors in that it is proposed to use an infiltrated graphitic structure, which has been developed for nuclear thermal propulsion reactor applications. In the accelerator based source the generation of spallation products and their activation levels, and the material damage sustained by the beam window will be investigated. (authors)

A highly accurate benchmark for reactor point kinetics with feedback

International Nuclear Information System (INIS)

Ganapol, B. D.; Picca, P.

2010-10-01

This work apply the concept of convergence acceleration, also known as extrapolation, to find the solution to the reactor kinetics equations describing nuclear reactor transients. The method features simplicity in that an approximate finite difference formulation is constructed and converged to high accuracy from knowledge of how the error term behaves. Through Rom berg extrapolation, we demonstrate its high accuracy for a variety of imposed reactivity insertions found in the literature as well as nonlinear temperature and fission product feedback. A unique feature of the proposed method, called RKE/R(om berg) algorithm, is interval bisection to ensure high accuracy. (Author)

Mechanical seal having a double-tier mating ring

Science.gov (United States)

Khonsari, Michael M.; Somanchi, Anoop K.

2005-09-13

An apparatus and method to enhance the overall performance of mechanical seals in one of the following ways: by reducing seal face wear, by reducing the contact surface temperature, or by increasing the life span of mechanical seals. The apparatus is a mechanical seal (e.g., single mechanical seals, double mechanical seals, tandem mechanical seals, bellows, pusher mechanical seals, and all types of rotating and reciprocating machines) comprising a rotating ring and a double-tier mating ring. In a preferred embodiment, the double-tier mating ring comprises a first and a second stationary ring that together form an agitation-inducing, guided flow channel to allow for the removal of heat generated at the seal face of the mating ring by channeling a coolant entering the mating ring to a position adjacent to and in close proximity with the interior surface area of the seal face of the mating ring.

An Evaluation Report on the High Temperature Design of the KALIMER-600 Reactor Structures

Energy Technology Data Exchange (ETDEWEB)

Park, Chang Gyu; Lee, Jae Han

2007-03-15

This report is on the validity evaluation of high temperature structural design for the reactor structures and piping of the pool-type Liquid Metal Reactor, KALIMER-600 subjected to the high temperature thermal load condition. The structural concept of the Upper Internal Structure located above the core is analyzed and the adequate UIS conceptual design for KALIMER-600 is proposed. Also, the high temperature structural integrity of the thermal liner which is to protect the UIS bottom plate from the high frequency thermal fatigue damage was evaluated by the thermal stripping analysis. The high temperature structural design of the reactor internal structure by considering the reactor startup-shutdown cycle was carried out and the structural integrity of it for a normal operating condition as well as the transient condition of the primary pump trip accident was confirmed. Additionally the structure design of the reactor internal structural was changed to prevent the non-uniform deformation of the primary pump which is induced by the thermal expansion difference between the reactor head and the baffle plate. The arrangement of the IHTS piping system which is a part of the reactor system is carried out and the structural integrity and the accumulated deformation by considering the reactor startup-shutdown cycle of a normal operating condition were evaluated. The structural integrity and the accumulated deformation of the PDRC hot leg piping by considering the PDRC operating condition were evaluated. The validity of KALIMER-600 high temperature structural design is confirmed through this study, and it is clearly found that the methodology research to evaluate the structural integrity considering the reactor life time of 60 years ensured is necessary.

High temperature helium-cooled fast reactor (HTHFR)

International Nuclear Information System (INIS)

Karam, R.A.; Blaylock, Dwayne; Burgett, Eric; Mostafa Ghiaasiaan, S.; Hertel, Nolan

2006-01-01

Scoping calculations have been performed for a very high temperature (1000 o C) helium-cooled fast reactor involving two distinct options: (1) using graphite foam into which UC (12% enrichment) is embedded into a matrix comprising UC and graphite foam molded into hexagonal building blocks and encapsulated with a SiC shell covering all surfaces, and (2) using UC only (also 12% enrichment) molded into the same shape and size as the foam-UC matrix in option 1. Both options use the same basic hexagonal fuel matrix blocks to form the core and reflector. The reflector contains natural uranium only. Both options use 50 μm SiC as a containment shell for fission product retention within each hexagonal block. The calculations show that the option using foam (option 1) would produce a reactor that can operate continuously for at least 25 years without ever adding or removing any fuel from the reactor. The calculations show further that the UC only option (option 2) can operate continually for 50 years without ever adding or removing fuel from the reactor. Doppler and loss of coolant reactivity coefficients were calculated. The Doppler coefficient is negative and much larger than the loss of coolant coefficient, which was very small and positive. Additional progress on and development of the two concepts are continuing

The development of high-temperature reactors in the Federal Republic of Germany

International Nuclear Information System (INIS)

Engelmann, P.; Krings, F.

1980-01-01

The principal features of high-temperature reactors are recalled, then the current state of technology of the line in the Federal Republic of Germany is described. Reference is made to the experience of operating the AVR reactor, the construction of the THTR-300 reactor as well as the HTT and PNP projects [fr

Advanced multi-physics simulation capability for very high temperature reactors

International Nuclear Information System (INIS)

Lee, Hyun Chul; Tak, Nam Il; Jo Chang Keun; Noh, Jae Man; Cho, Bong Hyun; Cho, Jin Woung; Hong, Ser Gi

2012-01-01

The purpose of this research is to develop methodologies and computer code for high-fidelity multi-physics analysis of very high temperature gas-cooled reactors(VHTRs). The research project was performed through Korea-US I-NERI program. The main research topic was development of methodologies for high-fidelity 3-D whole core transport calculation, development of DeCART code for VHTR reactor physics analysis, generation of VHTR specific 190-group cross-section library for DeCART code, development of DeCART/CORONA coupled code system for neutronics/thermo-fluid multi-physics analysis, and benchmark analysis against various benchmark problems derived from PMR200 reactor. The methodologies and the code systems will be utilized a key technologies in the Nuclear Hydrogen Development and Demonstration program. Export of code system is expected in the near future and the code systems developed in this project are expected to contribute to development and export of nuclear hydrogen production system

A high resolution pneumatic stepping actuator for harsh reactor environments

Science.gov (United States)

Tippetts, Thomas B.; Evans, Paul S.; Riffle, George K.

1993-01-01

A reactivity control actuator for a high-power density nuclear propulsion reactor must be installed in close proximity to the reactor core. The energy input from radiation to the actuator structure could exceed hundreds of W/cc unless low-cross section, low-absorptivity materials are chosen. Also, for post-test handling and subsequent storage, materials should not be used that are activated into long half-life isotopes. Pneumatic actuators can be constructed from various reactor-compatible materials, but conventional pneumatic piston actuators generally lack the stiffness required for high resolution reactivity control unless electrical position sensors and compensated electronic control systems are used. To overcome these limitations, a pneumatic actuator is under development that positions an output shaft in response to a series of pneumatic pulses, comprising a pneumatic analog of an electrical stepping motor. The pneumatic pulses are generated remotely, beyond the strong radiation environment, and transmitted to the actuator through tubing. The mechanically simple actuator uses a nutating gear harmonic drive to convert motion of small pistons directly to high-resolution angular motion of the output shaft. The digital nature of this actuator is suitable for various reactor control algorithms but is especially compatible with the three bean salad algorithm discussed by Ball et al. (1991).

The high moderating ratio reactor using 100% MOX reloads

International Nuclear Information System (INIS)

Barbrault, P.

1994-06-01

This report presents the concept of a High Moderating ratio Reactor, which should accept 100% MOX reloads. This reactor aims to be the plutonium version of the European Pressurized Reactor (EPR), which is developed jointly by French and German companies. A moderating ration of 2.5 (instead of the standard value of 2.0) is obtained by replacing several fuel rods by water holes. The core would contain 241 Fuel Assemblies. We present some advantages of over-moderation for plutonium fuel, a description of the core and assemblies, calculations of fuel reload schemes and Reactivity Shutdown Margins, and the behavior of the core during two occidental transients. (author). 2 refs., 9 figs., 2 tabs

Preliminary Demonstration Reactor Point Design for the Fluoride Salt-Cooled High-Temperature Reactor

Energy Technology Data Exchange (ETDEWEB)

Qualls, A. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Betzler, Benjamin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brown, Nicholas R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Carbajo, Juan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Greenwood, Michael Scott [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hale, Richard Edward [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Harrison, Thomas J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Powers, Jeffrey J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Robb, Kevin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrell, Jerry W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-12-01

Development of the Fluoride Salt-Cooled High-Temperature Reactor (FHR) Demonstration Reactor (DR) is a necessary intermediate step to enable commercial FHR deployment through disruptive and rapid technology development and demonstration. The FHR DR will utilize known, mature technology to close remaining gaps to commercial viability. Lower risk technologies are included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated within an acceptable budget and schedule. These technologies include tristructural-isotropic (TRISO) particle fuel, replaceable core structural material, the use of that same material for the primary and intermediate loops, and tube-and-shell heat exchangers. This report provides an update on the development of the FHR DR. At this writing, the core neutronics and thermal hydraulics have been developed and analyzed. The mechanical design details are still under development and are described to their current level of fidelity. It is anticipated that the FHR DR can be operational within 10 years because of the use of low-risk, near-term technology options.

Preliminary Demonstration Reactor Point Design for the Fluoride Salt-Cooled High-Temperature Reactor

International Nuclear Information System (INIS)

Qualls, A. L.; Betzler, Benjamin R.; Brown, Nicholas R.; Carbajo, Juan; Greenwood, Michael Scott; Hale, Richard Edward; Harrison, Thomas J.; Powers, Jeffrey J.; Robb, Kevin R.; Terrell, Jerry W.

2015-01-01

Development of the Fluoride Salt-Cooled High-Temperature Reactor (FHR) Demonstration Reactor (DR) is a necessary intermediate step to enable commercial FHR deployment through disruptive and rapid technology development and demonstration. The FHR DR will utilize known, mature technology to close remaining gaps to commercial viability. Lower risk technologies are included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated within an acceptable budget and schedule. These technologies include tristructural-isotropic (TRISO) particle fuel, replaceable core structural material, the use of that same material for the primary and intermediate loops, and tube-and-shell heat exchangers. This report provides an update on the development of the FHR DR. At this writing, the core neutronics and thermal hydraulics have been developed and analyzed. The mechanical design details are still under development and are described to their current level of fidelity. It is anticipated that the FHR DR can be operational within 10 years because of the use of low-risk, near-term technology options.

Collusion-Aware Privacy-Preserving Range Query in Tiered Wireless Sensor Networks†

Science.gov (United States)

Zhang, Xiaoying; Dong, Lei; Peng, Hui; Chen, Hong; Zhao, Suyun; Li, Cuiping

2014-01-01

Wireless sensor networks (WSNs) are indispensable building blocks for the Internet of Things (IoT). With the development of WSNs, privacy issues have drawn more attention. Existing work on the privacy-preserving range query mainly focuses on privacy preservation and integrity verification in two-tiered WSNs in the case of compromised master nodes, but neglects the damage of node collusion. In this paper, we propose a series of collusion-aware privacy-preserving range query protocols in two-tiered WSNs. To the best of our knowledge, this paper is the first to consider collusion attacks for a range query in tiered WSNs while fulfilling the preservation of privacy and integrity. To preserve the privacy of data and queries, we propose a novel encoding scheme to conceal sensitive information. To preserve the integrity of the results, we present a verification scheme using the correlation among data. In addition, two schemes are further presented to improve result accuracy and reduce communication cost. Finally, theoretical analysis and experimental results confirm the efficiency, accuracy and privacy of our proposals. PMID:25615731

Collusion-aware privacy-preserving range query in tiered wireless sensor networks.

Science.gov (United States)

Zhang, Xiaoying; Dong, Lei; Peng, Hui; Chen, Hong; Zhao, Suyun; Li, Cuiping

2014-12-11

Wireless sensor networks (WSNs) are indispensable building blocks for the Internet of Things (IoT). With the development of WSNs, privacy issues have drawn more attention. Existing work on the privacy-preserving range query mainly focuses on privacy preservation and integrity verification in two-tiered WSNs in the case of compromisedmaster nodes, but neglects the damage of node collusion. In this paper, we propose a series of collusion-aware privacy-preserving range query protocols in two-tiered WSNs. To the best of our knowledge, this paper is the first to consider collusion attacks for a range query in tiered WSNs while fulfilling the preservation of privacy and integrity. To preserve the privacy of data and queries, we propose a novel encoding scheme to conceal sensitive information. To preserve the integrity of the results, we present a verification scheme using the correlation among data. In addition, two schemes are further presented to improve result accuracy and reduce communication cost. Finally, theoretical analysis and experimental results confirm the efficiency, accuracy and privacy of our proposals.

Collusion-Aware Privacy-Preserving Range Query in Tiered Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Xiaoying Zhang

2014-12-01

Full Text Available Wireless sensor networks (WSNs are indispensable building blocks for the Internet of Things (IoT. With the development of WSNs, privacy issues have drawn more attention. Existing work on the privacy-preserving range query mainly focuses on privacy preservation and integrity verification in two-tiered WSNs in the case of compromisedmaster nodes, but neglects the damage of node collusion. In this paper, we propose a series of collusion-aware privacy-preserving range query protocols in two-tiered WSNs. To the best of our knowledge, this paper is the first to consider collusion attacks for a range query in tiered WSNs while fulfilling the preservation of privacy and integrity. To preserve the privacy of data and queries, we propose a novel encoding scheme to conceal sensitive information. To preserve the integrity of the results, we present a verification scheme using the correlation among data. In addition, two schemes are further presented to improve result accuracy and reduce communication cost. Finally, theoretical analysis and experimental results confirm the efficiency, accuracy and privacy of our proposals.

Impact of multi-tiered pharmacy benefits on attitudes of plan members with chronic disease states.

Science.gov (United States)

Nair, Kavita V; Ganther, Julie M; Valuck, Robert J; McCollum, Marianne M; Lewis, Sonya J

2002-01-01

To evaluate the effects of 2- and 3-tiered pharmacy benefit plans on member attitudes regarding their pharmacy benefits. We performed a mail survey and cross-sectional comparison of the outcome variables in a large managed care population in the western United States. Participants were persons with chronic disease states who were in 2- or 3-tier copay drug plans. A random sample of 10,662 was selected from a total of 25,008 members who had received 2 or more prescriptions for a drug commonly used to treat one of 5 conditions: hypertension, diabetes, dyslipidemia, gastroesophageal reflux disease (GERD), or arthritis. Statistical analysis included bivariate comparisons and regression analysis of the factors affecting member attitudes, including satisfaction, loyalty, health plan choices, and willingness to pay a higher out-of-pocket cost for medications. A response rate of 35.8% was obtained from continuously enrolled plan members. Respondents were older, sicker, and consumed more prescriptions than nonrespondents. There were significant differences in age and health plan characteristics between 2- and 3-tier plan members: respondents aged 65 or older represented 11.7% of 2-tier plan members and 54.7% of 3-tier plan members, and 10.0% of 2-tier plan members were in Medicare+Choice plans versus 61.4% in Medicare+Choice plans for 3-tier plan members (Pbrand-name medications, in general, they were not willing to pay more than 10 dollars (in addition to their copayment amount) for these medications. Older respondents and sicker individuals (those with higher scores on the Chronic Disease Indicator) appeared to have more positive attitudes toward their pharmacy benefit plans in general. Higher reported incomes by respondents were also associated with greater satisfaction with prescription drug coverage and increased loyalty toward the pharmacy benefit plan. Conversely, the more individuals spent for either their health care or prescription medications, the less satisfied

High-field, high-density tokamak power reactor

International Nuclear Information System (INIS)

Cohn, D.R.; Cook, D.L.; Hay, R.D.; Kaplan, D.; Kreischer, K.; Lidskii, L.M.; Stephany, W.; Williams, J.E.C.; Jassby, D.L.; Okabayashi, M.

1977-11-01

A conceptual design of a compact (R 0 = 6.0 m) high power density (average P/sub f/ = 7.7 MW/m 3 ) tokamak demonstration power reactor has been developed. High magnetic field (B/sub t/ = 7.4 T) and moderate elongation (b/a = 1.6) permit operation at the high density (n(0) approximately 5 x 10 14 cm -3 ) needed for ignition in a relatively small plasma, with a spatially-averaged toroidal beta of only 4%. A unique design for the Nb 3 Sn toroidal-field magnet system reduces the stress in the high-field trunk region, and allows modularization for simpler disassembly. The modest value of toroidal beta permits a simple, modularized plasma-shaping coil system, located inside the TF coil trunk. Heating of the dense central plasma is attained by the use of ripple-assisted injection of 120-keV D 0 beams. The ripple-coil system also affords dynamic control of the plasma temperature during the burn period. A FLIBE-lithium blanket is designed especially for high-power-density operation in a high-field environment, and gives an overall tritium breeding ratio of 1.05 in the slowly pumped lithium

Plant accident dynamics of high-temperature reactors with direct gas turbine cycle

International Nuclear Information System (INIS)

Waloch, M.L.

1977-01-01

In the paper submitted, a one-dimensional accident simulation model for high-temperature reactors with direct-cycle gas turbine (single-cycle facilities) is described. The paper assesses the sudden failure of a gas duct caused by the double-ended break of one out of several parallel pipes before and behind the reactor for a non-integrated plant, leading to major loads in the reactor region, as well as the complete loss of vanes of the compressor for an integrated plant. The results of the calculations show especially high loads for the break of a hot-gas pipe immediately behind the flow restrictors of the reactor outlet, because of prolonged effects of pressure gradients in the reactor region and the maximum core differential pressure. A plant accident dynamics calculation therefore allows to find a compromise between the requirements of stable compressor operation, on the one hand, and small loads in the reactor in the course of an accident, on the other, by establishing in a co-ordinated manner the narrowing ratio of the flow restrictors. (GL) [de

Considerations in the development of safety requirements for innovative reactors: Application to modular high temperature gas cooled reactors

International Nuclear Information System (INIS)

2003-08-01

Member States of the IAEA have frequently requested this organization to assess, at the conceptual stage, the safety of the design of nuclear reactors that rely on a variety of technologies and are of a high degree of innovation. However, to date, for advanced and innovative reactors and for reactors with characteristics that are different from those of existing light water reactors, widely accepted design standards and rules do not exist. This TECDOC is an outcome of the efforts deployed by the IAEA to develop a general approach for assessing the safety of the design of advanced and innovative reactors, and of all reactors in general including research reactors, with characteristics that differ from those of light water reactors. This publication puts forward a method for safety assessment that is based on the well established and accepted principle of defence in depth. The need to develop a general approach for assessing the safety of the design of reactors that applies to all kinds of advanced reactors was emphasized by the request to the IAEA by South Africa to review the safety of the South African pebble bed modular reactor. This reactor, as other modular high temperature gas cooled reactors (MHTGRs), adopts very specific design features such as the use of coated particle fuel. The characteristics of the fuel deeply affect the design and the safety of the plant, thereby posing several challenges to traditional safety assessment methods and to the application of existing safety requirements that have been developed primarily for water reactors. In this TECDOC, the MHTGR has been selected as a case study to demonstrate the viability of the method proposed. The approach presented is based on an extended interpretation of the concept of defence in depth and its link with the general safety objectives and fundamental safety functions as set out in 'Safety of Nuclear Power Plants: Design', IAEA Safety Standards No. NS-R.1, issued by the IAEA in 2000. The objective

Rhabdom evolution in butterflies: insights from the uniquely tiered and heterogeneous ommatidia of the Glacial Apollo butterfly, Parnassius glacialis.

Science.gov (United States)

Matsushita, Atsuko; Awata, Hiroko; Wakakuwa, Motohiro; Takemura, Shin-ya; Arikawa, Kentaro

2012-09-07

The eye of the Glacial Apollo butterfly, Parnassius glacialis, a 'living fossil' species of the family Papilionidae, contains three types of spectrally heterogeneous ommatidia. Electron microscopy reveals that the Apollo rhabdom is tiered. The distal tier is composed exclusively of photoreceptors expressing opsins of ultraviolet or blue-absorbing visual pigments, and the proximal tier consists of photoreceptors expressing opsins of green or red-absorbing visual pigments. This organization is unique because the distal tier of other known butterflies contains two green-sensitive photoreceptors, which probably function in improving spatial and/or motion vision. Interspecific comparison suggests that the Apollo rhabdom retains an ancestral tiered pattern with some modification to enhance its colour vision towards the long-wavelength region of the spectrum.

Proposed upgrade of the lower tier water moderators for the LANSE 1L MARK-III upgrade

International Nuclear Information System (INIS)

Muhrer, G.; Pitcher, E.J.; Russell, G.J.

2005-01-01

We will show in this article the proposed upgrade for the lower tier water moderators for the LANSCE 1L Mark-III design. This proposal will include the introduction of pre-moderators for the high intensity moderators and a change of the decoupler from Cadmium to Gadolinium on all lower tier water moderators. We will present the influence of these changes on the integrated thermal flux and the time distribution of these moderators. As part of the upgrade of the Manual Lujan Jr. Neutron Scattering Center target (1L target) the goal was to increase the integrated thermal flux of the lower high intensity and the high resolution moderator by 20%. We will show in this paper that this goal can be achieved by introducing a pre-moderator concept on the high resolution moderators and by changing the decoupling scheme on all three moderators. Furthermore we will show that this goal can be achieved without jeopardizing the time of flight resolution of these moderators. For the all these calculations we used the radiation transport code MCNPX, which is most commonly used for this type of calculations.

Process heat cogeneration using a high temperature reactor

International Nuclear Information System (INIS)

Alonso, Gustavo; Ramirez, Ramon; Valle, Edmundo del; Castillo, Rogelio

2014-01-01

Highlights: • HTR feasibility for process heat cogeneration is assessed. • A cogeneration coupling for HTR is proposed and process heat cost is evaluated. • A CCGT process heat cogeneration set up is also assessed. • Technical comparison between both sources of cogeneration is performed. • Economical competitiveness of the HTR for process heat cogeneration is analyzed. - Abstract: High temperature nuclear reactors offer the possibility to generate process heat that could be used in the oil industry, particularly in refineries for gasoline production. These technologies are still under development and none of them has shown how this can be possible and what will be the penalty in electricity generation to have this additional product and if the cost of this subproduct will be competitive with other alternatives. The current study assesses the likeliness of generating process heat from Pebble Bed Modular Reactor to be used for a refinery showing different plant balances and alternatives to produce and use that process heat. An actual practical example is presented to demonstrate the cogeneration viability using the fact that the PBMR is a modular small reactor where the cycle configuration to transport the heat of the reactor to the process plant plays an important role in the cycle efficiency and in the plant economics. The results of this study show that the PBMR would be most competitive when capital discount rates are low (5%), carbon prices are high (>30 US$/ton), and competing natural gas prices are at least 8 US$/mmBTU

Process heat cogeneration using a high temperature reactor

Energy Technology Data Exchange (ETDEWEB)

Alonso, Gustavo, E-mail: gustavoalonso3@gmail.com [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, Ocoyoacac, Edo. De Mexico 52750 (Mexico); Instituto Politécnico Nacional, Unidad Profesional Adolfo Lopez Mateos, Ed. 9, Lindavista, D.F. 07300 (Mexico); Ramirez, Ramon [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, Ocoyoacac, Edo. De Mexico 52750 (Mexico); Valle, Edmundo del [Instituto Politécnico Nacional, Unidad Profesional Adolfo Lopez Mateos, Ed. 9, Lindavista, D.F. 07300 (Mexico); Castillo, Rogelio [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, Ocoyoacac, Edo. De Mexico 52750 (Mexico)

2014-12-15

Highlights: • HTR feasibility for process heat cogeneration is assessed. • A cogeneration coupling for HTR is proposed and process heat cost is evaluated. • A CCGT process heat cogeneration set up is also assessed. • Technical comparison between both sources of cogeneration is performed. • Economical competitiveness of the HTR for process heat cogeneration is analyzed. - Abstract: High temperature nuclear reactors offer the possibility to generate process heat that could be used in the oil industry, particularly in refineries for gasoline production. These technologies are still under development and none of them has shown how this can be possible and what will be the penalty in electricity generation to have this additional product and if the cost of this subproduct will be competitive with other alternatives. The current study assesses the likeliness of generating process heat from Pebble Bed Modular Reactor to be used for a refinery showing different plant balances and alternatives to produce and use that process heat. An actual practical example is presented to demonstrate the cogeneration viability using the fact that the PBMR is a modular small reactor where the cycle configuration to transport the heat of the reactor to the process plant plays an important role in the cycle efficiency and in the plant economics. The results of this study show that the PBMR would be most competitive when capital discount rates are low (5%), carbon prices are high (>30 US$/ton), and competing natural gas prices are at least 8 US$/mmBTU.

Fabrication of high performance components for Indian nuclear reactors

International Nuclear Information System (INIS)

Jayaraj, R.N.

2011-01-01

Nuclear Fuel Complex (NFC), a Unit of the Department of Atomic Energy (DAE) has been engaged for well over three-and-half decades in the manufacture of fuels for Pressurized Heavy Water Reactors (PHWRs) and Boiling Water Reactors (BWRs). All the fuel assembly components, like, fuel clad tubes, end plugs, spacers, spacer grids etc. are also being manufactured at NFC in Zirconium alloy material. Apart from the regular production of these components and finished fuel assemblies, NFC has also been engaged in the production of Zirconium alloy reactor core structurals, like, pressure tubes, calandria tubes, garter springs and reactivity control mechanisms for PHWRs and square channels for BWRs. While all these structural components are produced through standardized flow sheets, there have been continuous innovations carried out in the processes to meet the ever increasing end-use characteristics laid down by the utilities. The paper enumerates various aspects of different technologies developed at NFC for the manufacture of high performance components for reactor applications

Present state and future prospect of development of high temperature gas-cooled reactors in Japan

International Nuclear Information System (INIS)

Sanokawa, Konomo

1994-01-01

High temperature gas-cooled reactors can supply the heat of about 1000degC, and the high efficiency and the high rate of heat utilization can be attained. Also they have the features of excellent inherent safety, the easiness of operation, the high burnup of fuel and so on. The heat utilization of atomic energy in addition to electric power generation is very important in view of the protection of global environment and the diversification of energy supply. Japan Atomic Energy Research Institute has advanced the construction of the high temperature engineering test and research reactor (HTTR) of 30 MW thermal output, aiming at attaining the criticality in 1998. The progress of the development of a high temperature gas-cooled reactor is described. For 18 years, the design study of the reactor was advanced together with the research and development of the reactor physics, fuel and materials, high temperature machinery and equipment and others, and the decision of the design standard and the development of computation codes. The main specification and the construction schedule are shown. The reactor building was almost completed, and the reactor containment vessel was installed. The plan of the research and development by using the HTTR is investigated. (K.I.)

Technology assessment HTR. Part 4. Power upscaling of High Temperature Reactors

International Nuclear Information System (INIS)

Van Heek, A.I.

1996-06-01

Designs of nuclear reactors can be classified in evolutionary, revolutionary and innovative designs. An innovative design is the High Temperature Reactor (HTR). Introduction of innovative reactors has not been successful until now. Globally, three requirements for this reactors for successful market introduction can be identified: (1) Societal support for nuclear energy, or if separable, for this reactor type, should be repaired; (2) After market introduction the innovative plant must be able to operate economically competitive; and (3) The costs of market introduction of an innovative reactor design must be limited. Until now all reactor designs classified as innovative have not yet been realized. High temperature reactors exist in many different designs. Common features are: helium coolant, graphite moderator and coated particle fuel. The combination of these creates the potential to fulfill the first requirement (public support), and similarly a hurdle to the second requirement (economical operation). All three problems existing in the eyes of the public are addressed, while a high degree of transparency is reached, making the design understandable also by others than nuclear experts. A consequence of designing according to the social support requirement is a limitation of the unit power level. The usual method to make nuclear power plants economically competitive, i.e. just raising the power level (economy of scale) could not be applied anymore. Therefore other means of cost decreasing had to be used: modularization and simplification. These ideas are explained. Since all existing HTRs are currently out of operation, additional experience from two small HTRs under construction at this moment in the Far East will be essential. In the history of HTR designs, an evolutionary path can be identified. The early designs had a philosophy of safety and economics very similar to those of LWR. Modularization was introduced to attain economic viability and the design was

The KFA TierPET: Performance characteristics and measurements

International Nuclear Information System (INIS)

Weber, S.; Herzog, H.; Mueller-Gaertner, H.W.

1996-01-01

We will present first results of the KFA Tier-PET, a positron emission tomograph with flexible geometry dedicated to in vivo studies of small animals. The flexible geometry allows us to change between measurements with high spatial resolution and measurements with increased sensitivity at the cost of resolution. The detectors consist of yttrium aluminum perovskit scintillator arrays which are glued together from 20 x 20 optically isolated crystals, coupled to position sensitive photomultiplier tubes. The fundamental design features concerning crystal dimensions and detector arrangement have been simulated. Based on this data, the definite dimensional outline of the crystals was determined. The YAP:Ce matrix in combination with a position sensitive photomultiplier leads to a detector block with a high spatial resolution. In first measurements a system sensitivity of 1.8 kcps/μCi/ml has been evaluated for a detector-to-detector distance of 16 cm

Testing SLURM open source batch system for a Tierl/Tier2 HEP computing facility

International Nuclear Information System (INIS)

Donvito, Giacinto; Italiano, Alessandro; Salomoni, Davide

2014-01-01

In this work the testing activities that were carried on to verify if the SLURM batch system could be used as the production batch system of a typical Tier1/Tier2 HEP computing center are shown. SLURM (Simple Linux Utility for Resource Management) is an Open Source batch system developed mainly by the Lawrence Livermore National Laboratory, SchedMD, Linux NetworX, Hewlett-Packard, and Groupe Bull. Testing was focused both on verifying the functionalities of the batch system and the performance that SLURM is able to offer. We first describe our initial set of requirements. Functionally, we started configuring SLURM so that it replicates all the scheduling policies already used in production in the computing centers involved in the test, i.e. INFN-Bari and the INFN-Tier1 at CNAF, Bologna. Currently, the INFN-Tier1 is using IBM LSF (Load Sharing Facility), while INFN-Bari, an LHC Tier2 for both CMS and Alice, is using Torque as resource manager and MAUI as scheduler. We show how we configured SLURM in order to enable several scheduling functionalities such as Hierarchical FairShare, Quality of Service, user-based and group-based priority, limits on the number of jobs per user/group/queue, job age scheduling, job size scheduling, and scheduling of consumable resources. We then show how different job typologies, like serial, MPI, multi-thread, whole-node and interactive jobs can be managed. Tests on the use of ACLs on queues or in general other resources are then described. A peculiar SLURM feature we also verified is triggers on event, useful to configure specific actions on each possible event in the batch system. We also tested highly available configurations for the master node. This feature is of paramount importance since a mandatory requirement in our scenarios is to have a working farm cluster even in case of hardware failure of the server(s) hosting the batch system. Among our requirements there is also the possibility to deal with pre-execution and post

Testing SLURM open source batch system for a Tierl/Tier2 HEP computing facility

Science.gov (United States)

Donvito, Giacinto; Salomoni, Davide; Italiano, Alessandro

2014-06-01

In this work the testing activities that were carried on to verify if the SLURM batch system could be used as the production batch system of a typical Tier1/Tier2 HEP computing center are shown. SLURM (Simple Linux Utility for Resource Management) is an Open Source batch system developed mainly by the Lawrence Livermore National Laboratory, SchedMD, Linux NetworX, Hewlett-Packard, and Groupe Bull. Testing was focused both on verifying the functionalities of the batch system and the performance that SLURM is able to offer. We first describe our initial set of requirements. Functionally, we started configuring SLURM so that it replicates all the scheduling policies already used in production in the computing centers involved in the test, i.e. INFN-Bari and the INFN-Tier1 at CNAF, Bologna. Currently, the INFN-Tier1 is using IBM LSF (Load Sharing Facility), while INFN-Bari, an LHC Tier2 for both CMS and Alice, is using Torque as resource manager and MAUI as scheduler. We show how we configured SLURM in order to enable several scheduling functionalities such as Hierarchical FairShare, Quality of Service, user-based and group-based priority, limits on the number of jobs per user/group/queue, job age scheduling, job size scheduling, and scheduling of consumable resources. We then show how different job typologies, like serial, MPI, multi-thread, whole-node and interactive jobs can be managed. Tests on the use of ACLs on queues or in general other resources are then described. A peculiar SLURM feature we also verified is triggers on event, useful to configure specific actions on each possible event in the batch system. We also tested highly available configurations for the master node. This feature is of paramount importance since a mandatory requirement in our scenarios is to have a working farm cluster even in case of hardware failure of the server(s) hosting the batch system. Among our requirements there is also the possibility to deal with pre-execution and post

High temperature and high performance light water cooled reactors operating at supercritical pressure, research and development

International Nuclear Information System (INIS)

Oka, Y.; Koshizuka, S.; Katsumura, Y.; Yamada, K.; Shiga, S.; Moriya, K.; Yoshida, S.; Takahashi, H.

2003-01-01

The concept of supercritical-pressure, once-through coolant cycle nuclear power plant (SCR) was developed at the University of Tokyo. The research and development (R and D) started worldwide. This paper summarized the conceptual design and R and D in Japan. The big advantage of the SCR concept is that the temperatures of major components such as reactor pressure vessel, control rod drive mechanisms, containments, coolant pumps, main steam piping and turbines are within the temperatures of the components of LWR and supercritical fossil fired power plants (FPP) in spite of the high outlet coolant temperature. The experience of these components of LWR and supercritical fossil fired power plants will be fully utilized for SCR. The high temperature, supercritical-pressure light water reactor is the logical evolution of LWR. Boiling evolved from circular boilers, water tube boilers and once-through boilers. It is the reactor version of the once-through boiler. The development from LWR to SCR follows the history of boilers. The goal of the R and D should be the capital cost reduction that cannot be achieved by the improvement of LWR. The reactor can be used for hydrogen production either by catalysis and chemical decomposition of low quality hydrocarbons in supercritical water. The reactor is compatible with tight lattice fast core for breeders due to low outlet coolant density, small coolant flow rate and high head coolant pumps

Professional Development to Differentiate Kindergarten Tier 1 Instruction: Can Already Effective Teachers Improve Student Outcomes by Differentiating Tier 1 Instruction?

Science.gov (United States)

Al Otaiba, Stephanie; Folsom, Jessica S.; Wanzek, Jeanne; Greulich, Luana; Waesche, Jessica; Schatschneider, Christopher; Connor, Carol M.

2016-01-01

Two primary purposes guided this quasi-experimental within-teacher study: (a) to examine changes from baseline through 2 years of professional development (Individualizing Student Instruction) in kindergarten teachers' differentiation of Tier 1 literacy instruction; and (b) to examine changes in reading and vocabulary of 3 cohorts of the teachers'…

Status of the design concepts for a high fluence fast pulse reactor (HFFPR)

International Nuclear Information System (INIS)

Philbin, J.S.; Nelson, W.E.; Rosenstroch, B.

1978-10-01

The report describes progress that has been made on the design of a High Fluence Fast Pulse Reactor (HFFPR) through the end of calendar year 1977. The purpose of this study is to present design concepts for a test reactor capable of accommodating large scale reactor safety tests. These concepts for reactor safety tests are adaptations of reactor concepts developed earlier for DOE/OMA for the conduct of weapon effects tests. The preferred driver core uses fuel similar to that developed for Sandia's ACPR upgrade. It is a BeO/UO 2 fuel that is gas cooled and has a high volumetric heat capacity. The present version of the design can drive large (217) pin bundles of prototypically enriched mixed oxide fuel well beyond the fuel's boiling point. Applicability to specific reactor safety accident scenarios and subsequent design improvements will be presented in future reports on this subject

Dynamics three-tier hydraulic crane-manipulators

OpenAIRE

Lagerev I.A.; Lagerev A.V.

2018-01-01

The methods and generalized recommendations for modeling dynamic loading of load-bearing elements of steel structures of three-tier hydraulic cranes-manipulators are considered. Mathematical models have been developed to study the dynamics of moving elements of the crane-manipulator, the movement of the load-lifting machine on a stochastic uneven surface with a suspended load. The presented approaches can be used to calculate other types of jib cranes equipped with hydraulic drive.

Communication costs in a multi-tiered MPSoC

NARCIS (Netherlands)

van de Burgwal, M.D.; Smit, Gerardus Johannes Maria

2008-01-01

The amount of digital processing required for phased array beamformers is very large. It requires many parallel processors, which can be organized in a multi-tiered structure. Communication costs differ for each of the stages in such an architecture. For example, communication costs from the antenna

Compatibility of steels for fast breeder reactor in high temperature sodium

International Nuclear Information System (INIS)

Yuhara, Shunichi

1981-01-01

In recent years, considerable progress has been made and experience has been obtained for material applicability in sodium-cooled fast breeder reactors. In this report, materials, principal dimensions and sodium conditions for the reactor system components, which include fuel pin cladding, intermediate heat exchangers, steam generators and pipings, are reviewed with emphasis on the thin-walled, high temperature and high strength components. The corrosion, mechanical and tribological behavior in sodium of important materials used for the reactor components, such as Types 304 and 316 stainless steel and 2 1/4Cr-1Mo steel, are discussed on the basis of characteristic testing results. Furthermore, material requirements concerned with compatibility in sodium are summarized from this review and discussion. (author)

Decommissioning of the High Flux Beam Reactor at Brookhaven Lab

Energy Technology Data Exchange (ETDEWEB)

Hu, J. P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Reciniello, R. N. [Brookhaven National Lab. (BNL), Upton, NY (United States); Holden, N. E. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2011-05-27

The High Flux Beam Reactor at the Brookhaven National Laboratory was a heavy water cooled and moderated reactor that achieved criticality on October 31, 1965. It operated at a power level of 40 mega-watts. An equipment upgrade in 1982 allowed operations at 60 mega-watts. After a 1989 reactor shutdown to reanalyze safety impact of a hypothetical loss of coolant accident, the reactor was restarted in 1991 at 30 mega-watts. The HFBR was shutdown in December 1996 for routine maintenance and refueling. At that time, a leak of tritiated water was identified by routine sampling of ground water from wells located adjacent to the reactor’s spent fuel pool. The reactor remained shutdown for almost three years for safety and environmental reviews. In November 1999 the United States Department of Energy decided to permanently shutdown the HFBR. The decontamination and decommissioning of the HFBR complex, consisting of multiple structures and systems to operate and maintain the reactor, were complete in 2009 after removing and shipping off all the control rod blades. The emptied and cleaned HFBR dome which still contains the irradiated reactor vessel is presently under 24/7 surveillance for safety. Details of the HFBR cleanup conducted during 1999-2009 will be described in the paper.

A probabilistic consequence assessment for a very high temperature reactor

Energy Technology Data Exchange (ETDEWEB)

Lee, Joeun; Kim, Jintae; Jae, Moosung [Hanyang Univ., Seoul (Korea, Republic of). Dept. of Nuclear Engineering

2017-02-15

Currently, fossil fuel is globally running out. If current trends continue, crude oil will be depleted in 20 years and natural gas in 40 years. In addition, the use of fossil resource has increased emissions of green gas such as carbon dioxide. Therefore, there has been a strong demand in recent years for producing large amounts of hydrogen as an alternative energy [1]. To generate hydrogen energy, very high temperature more than 900 C is required but this level is not easy to reach. Because a Very High Temperature Reactor (VHTR), one of next generation reactor, is able to make the temperature, it is regarded as a solution of the problem. Also, VHTR has an excellent safety in comparison with existing and other next generation reactors. Especially, a passive system, Reactor Cavity Cooling System (RCCS), is adopted to get rid of radiant heat in case of accidents. To achieve variety requirements of new designed-reactors, however, it needs to develop new methodologies and definitions different with existing method. At the same time, an application of probability safety assessment (PSA) has been proposed to ensure the safety of next generation NPPs. For this, risk-informed designs of structures have to be developed and verified. Particularly, the passive system requires to be evaluated for its reliability. The objective of this study is to improve safety of VIITR by conducting risk profile.

WHALE, a management tool for Tier-2 LCG sites

Science.gov (United States)

Barone, L. M.; Organtini, G.; Talamo, I. G.

2012-12-01

The LCG (Worldwide LHC Computing Grid) is a grid-based hierarchical computing distributed facility, composed of more than 140 computing centers, organized in 4 tiers, by size and offer of services. Every site, although indipendent for many technical choices, has to provide services with a well-defined set of interfaces. For this reason, different LCG sites need frequently to manage very similar situations, like jobs behaviour on the batch system, dataset transfers between sites, operating system and experiment software installation and configuration, monitoring of services. In this context we created WHALE (WHALE Handles Administration in an LCG Environment), a software actually used at the T2_IT_Rome site, an LCG Tier-2 for the CMS experiment. WHALE is a generic, site independent tool written in Python: it allows administrator to interact in a uniform and coherent way with several subsystems using a high level syntax which hides specific commands. The architecture of WHALE is based on the plugin concept and on the possibility of connecting the output of a plugin to the input of the next one, in a pipe-like system, giving the administrator the possibility of making complex functions by combining the simpler ones. The core of WHALE just handles the plugin orchestrations, while even the basic functions (eg. the WHALE activity logging) are performed by plugins, giving the capability to tune and possibly modify every component of the system. WHALE already provides many plugins useful for a LCG site and some more for a Tier-2 of the CMS experiment, especially in the field of job management, dataset transfer and analysis of performance results and availability tests (eg. Nagios tests, SAM tests). Thanks to its architecture and the provided plugins WHALE makes easy to perform tasks that, even if logically simple, are technically complex or tedious, like eg. closing all the worker nodes with a job-failure rate greater than a given threshold. Finally, thanks to the

The concept of fuel cycle integrated molten salt reactor for transmuting Pu+MA from spent LWR fuels

International Nuclear Information System (INIS)

Hirose, Y.; Takashima, Y.

2001-01-01

Japan should need a new fuel cycle, not to save spent fuels indefinitely as the reusable resources but to consume plutonium and miner actinides orderly without conventional reprocessing. The key component is a molten salt reactor fueled with the Pu+MA (PMA) separated from LWR spent fuels using fluoride volatility method. A double-tiered once-through reactor system can burn PMA down to 5% remnant ratio, and can make PMA virtually free from the HAW to be disposed geometrically. A key issue to be demonstrated is the first of all solubility behavior of trifluoride species in the molten fuel salt of 7 LiF-BeF 2 mixture. (author)

High-intensity power-resolved radiation imaging of an operational nuclear reactor

OpenAIRE

Beaumont, Jonathan; Villa, Mario; Mellor, Matthew; Joyce, Malcolm John

2015-01-01

Knowledge of the neutron distribution in a nuclear reactor is necessary to ensure the safe and efficient burnup of reactor fuel. Currently these measurements are performed by in-core systems in what are extremely hostile environments and in most reactor accident scenarios it is likely that these systems would be damaged. Here we present a compact and portable radiation imaging system with the ability to image high-intensity fast-neutron and gamma-ray fields simultaneously. This system has bee...

HTR-2002: Proceedings of the conference on high temperature reactors

International Nuclear Information System (INIS)

2002-01-01

High temperature reactors are considered as future inherently safe and efficient energy sources. The presentations covered all the relevant aspects of the existing HTGRs and/or helium cooled pebble bed reactors. They were sorted into 7 sessions: HTR Projects and Programmes; Fuel and Fuel Cycle; Physics and Neutronics; Thermohydraulic Calculation; Engineering, Design and Applications; Materials and Components; Safety and Licensing

Design and development of gas turbine high temperature reactor 300 (GTHTR300)

International Nuclear Information System (INIS)

Kunitomi, Kazuhiko; Katanishi, Shoji; Takada, Shoji; Takizuka, Takakazu; Yan, Xing; Kosugiyama, Shinichi

2003-01-01

JAERI (Japan Atomic Energy Research Institute) started design and development of the high temperature gas cooled reactor with a gas turbine electric generation system, GTHTR300, in April 2001. Design originalities of the GTHTR300 are a horizontally mounted highly efficient gas turbine system and an ultimately simplified safety system such as no containment building and no active emergency core cooling. These design originalities are proposed based on design and operational experiences in conventional gas turbine systems and Japan's first high temperature gas cooled reactor (HTTR: High Temperature Engineering Test Reactor) so that many R and Ds are not required for the development. Except these original design features, devised core design, fuel design and plant design are adopted to meet design requirements and attain a target cost. This paper describes the unique design features focusing on the safety design, reactor core design and gas turbine system design together with a preliminary result of the safety evaluation carried out for a typical severe event. This study is entrusted from Ministry of Education, Culture, Sports, Science and Technology of Japan. (author)

External event Probabilistic Risk Assessment for the High Flux Isotope Reactor (HFIR)

International Nuclear Information System (INIS)

Flanagan, G.F.; Johnson, D.H.; Buttemer, D.; Perla, H.F.; Chien, S.H.

1989-01-01

The High Flux Isotope Reactor (HFIR) is a high performance isotope production and research reactor which has been in operation at Oak Ridge National Laboratory (ORNL) since 1965. In late 1986 the reactor was shut down as a result of discovery of unexpected neutron embrittlement of the reactor vessel. In January of 1988 a level 1 Probabilistic Risk Assessment (PRA) (excluding external events) was published as part of the response to the many reviews that followed the shutdown and for use by ORNL to prioritize action items intended to upgrade the safety of the reactor. A conservative estimate of the core damage frequency initiated by internal events for HFIR was 3.11 x 10 -4 . In June 1989 a draft external events initiated PRA was published. The dominant contributions from external events came from seismic, wind, and fires. The overall external event contribution to core damage frequency is about 50% of the internal event initiated contribution and is dominated by seismic events

Low-complexity co-tier interference reduction scheme in open-access overlaid cellular networks

KAUST Repository

Radaydeh, Redha Mahmoud Mesleh

2011-12-01

This paper addresses the effect of co-tier interference on the performance of multiuser overlaid cellular networks that share the same available resources. It assumed that each macrocell contains a number of self-configurable and randomly located femtocells that employ the open-access control strategy to reduce the effect of cross-tier interference. It is also assumed that the desired user equipment (UE) can access only one of the available channels, maintains simple decoding circuitry with single receive antenna, and has limited knowledge of the instantaneous channel state information (CSI) due to resource limitation. To mitigate the effect of co-tier interference in the absence of the CSI of the desired UE, a low-complexity switched-based scheme for single channel selection based on the predicted interference levels associated with available channels is proposed for the case of over-loaded channels. Through the analysis, new general formulation for the statistics of the resulting instantaneous interference power and some performance measures are presented. The effect of the switching threshold on the efficiency and performance of the proposed scheme is studied. Numerical and simulation results to clarify the usefulness of the proposed scheme in reducing the impact of co-tier interference are also provided. © 2011 IEEE.

High-temperature gas-cooled reactor safety-reliability program plan

Energy Technology Data Exchange (ETDEWEB)

1981-03-01

The purpose of this document is to present a safety plan as part of an overall program plan for the design and development of the High Temperature Gas-Cooled Reactor (HTGR). This plan is intended to establish a logical framework for identifying the technology necessary to demonstrate that the requisite degree of public risk safety can be achieved economically. This plan provides a coherent system safety approach together with goals and success criterion as part of a unifying strategy for licensing a lead reactor plant in the near term. It is intended to provide guidance to program participants involved in producing a technology base for the HTGR that is fully responsive to safety consideration in the design, evaluation, licensing, public acceptance, and economic optimization of reactor systems.

Enrichment of acetogenic bacteria in high rate anaerobic reactors under mesophilic and thermophilic conditions.

Science.gov (United States)

Ryan, P; Forbes, C; McHugh, S; O'Reilly, C; Fleming, G T A; Colleran, E

2010-07-01

The objective of the current study was to expand the knowledge of the role of acetogenic Bacteria in high rate anaerobic digesters. To this end, acetogens were enriched by supplying a variety of acetogenic growth supportive substrates to two laboratory scale high rate upflow anaerobic sludge bed (UASB) reactors operated at 37 degrees C (R1) and 55 degrees C (R2). The reactors were initially fed a glucose/acetate influent. Having achieved high operational performance and granular sludge development and activity, both reactors were changed to homoacetogenic bacterial substrates on day 373 of the trial. The reactors were initially fed with sodium vanillate as a sole substrate. Although % COD removal indicated that the 55 degrees C reactor out performed the 37 degrees C reactor, effluent acetate levels from R2 were generally higher than from R1, reaching values as high as 5023 mg l(-1). Homoacetogenic activity in both reactors was confirmed on day 419 by specific acetogenic activity (SAA) measurement, with higher values obtained for R2 than R1. Sodium formate was introduced as sole substrate to both reactors on day 464. It was found that formate supported acetogenic activity at both temperatures. By the end of the trial, no specific methanogenic activity (SMA) was observed against acetate and propionate indicating that the methane produced was solely by hydrogenotrophic Archaea. Higher SMA and SAA values against H(2)/CO(2) suggested development of a formate utilising acetogenic population growing in syntrophy with hydrogenotrophic methanogens. Throughout the formate trial, the mesophilic reactor performed better overall than the thermophilic reactor. Copyright 2010 Elsevier Ltd. All rights reserved.

Baseline Concept Description of a Small Modular High Temperature Reactor

Energy Technology Data Exchange (ETDEWEB)

Gougar, Hans D. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2014-10-01

The objective of this report is to provide a description of generic small modular high temperature reactors (herein denoted as an smHTR), summarize their distinguishing attributes, and lay out the research and development (R&D) required for commercialization. The generic concepts rely heavily on the modular high temperature gas-cooled reactor designs developed in the 1980s which were never built but for which pre-licensing or certification activities were conducted. The concept matured more recently under the Next Generation Nuclear Plant (NGNP) project, specifically in the areas of fuel and material qualification, methods development, and licensing. As all vendor-specific designs proposed under NGNP were all both ‘small’ or medium-sized and ‘modular’ by International Atomic Energy Agency (IAEA) and Department of Energy (DOE) standards, the technical attributes, challenges, and R&D needs identified, addressed, and documented under NGNP are valid and appropriate in the context of Small Modular Reactor (SMR) applications. Although the term High Temperature Reactor (HTR) is commonly used to denote graphite-moderated, thermal spectrum reactors with coolant temperatures in excess of 650oC at the core outlet, in this report the historical term High Temperature Gas-Cooled Reactor (HTGR) will be used to distinguish the gas-cooled technology described herein from its liquid salt-cooled cousin. Moreover, in this report it is to be understood that the outlet temperature of the helium in an HTGR has an upper limit of 950 degrees C which corresponds to the temperature to which certain alloys are currently being qualified under DOE’s ARC program. Although similar to the HTGR in just about every respect, the Very High Temperature Reactor (VHTR) may have an outlet temperature in excess of 950 degrees C and is therefore farther from commercialization because of the challenges posed to materials exposed to these temperatures. The VHTR is the focus of R&D under the

Baseline Concept Description of a Small Modular High Temperature Reactor

Energy Technology Data Exchange (ETDEWEB)

Hans Gougar

2014-05-01

The objective of this report is to provide a description of generic small modular high temperature reactors (herein denoted as an smHTR), summarize their distinguishing attributes, and lay out the research and development (R&D) required for commercialization. The generic concepts rely heavily on the modular high temperature gas-cooled reactor designs developed in the 1980s which were never built but for which pre-licensing or certification activities were conducted. The concept matured more recently under the Next Generation Nuclear Plant (NGNP) project, specifically in the areas of fuel and material qualification, methods development, and licensing. As all vendor-specific designs proposed under NGNP were all both ‘small’ or medium-sized and ‘modular’ by International Atomic Energy Agency (IAEA) and Department of Energy (DOE) standards, the technical attributes, challenges, and R&D needs identified, addressed, and documented under NGNP are valid and appropriate in the context of Small Modular Reactor (SMR) applications. Although the term High Temperature Reactor (HTR) is commonly used to denote graphite-moderated, thermal spectrum reactors with coolant temperatures in excess of 650oC at the core outlet, in this report the historical term High Temperature Gas-Cooled Reactor (HTGR) will be used to distinguish the gas-cooled technology described herein from its liquid salt-cooled cousin. Moreover, in this report it is to be understood that the outlet temperature of the helium in an HTGR has an upper limit of 950 degrees C which corresponds to the temperature to which certain alloys are currently being qualified under DOE’s ARC program. Although similar to the HTGR in just about every respect, the Very High Temperature Reactor (VHTR) may have an outlet temperature in excess of 950 degrees C and is therefore farther from commercialization because of the challenges posed to materials exposed to these temperatures. The VHTR is the focus of R&D under the

The Development and Validation of a Three-Tier Diagnostic Test Measuring Pre-Service Elementary Education and Secondary Science Teachers' Understanding of the Water Cycle

Science.gov (United States)

Schaffer, Dannah Lynn

2013-01-01

The main goal of this research study was to develop and validate a three-tier diagnostic test to determine pre-service teachers' (PSTs) conceptual knowledge of the water cycle. For a three-tier diagnostic test, the first tier assesses content knowledge; in the second tier, a reason is selected for the content answer; and the third tier allows…

Feasibility study of high temperature reactor utilization in Czech Republic after 2025

Energy Technology Data Exchange (ETDEWEB)

Losa, Evžen, E-mail: evzen.losa@fjfi.cvut.cz [Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Department of Nuclear Reactors (Czech Republic); Heřmanský, Bedřich; Kobylka, Dušan; Rataj, Jan; Sklenka, Ľubomír [Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Department of Nuclear Reactors (Czech Republic); Souček, Václav; Kohout, Petr [AZIN CZ, s.r.o., Hanusova 3, 140 00 Praha 4 (Czech Republic)

2014-05-01

High temperature reactors (HTRs) were examined as an option to intended future broadening of the nuclear energy production in Czech Republic. The known qualities as the inherent safety, high thermal utilization and non-electrical applications have been assessed in years 2009–2011 during the survey funded by Czech Ministry of Industry and Trade. The survey of high temperature reactors with spherical fuel was initiated by reason of mature state of the art of this technology type in South Africa and in China, where in both countries pilot plants were planned. Unfortunately, the global financial crisis caused the decision of stopping the governmental support in South African programme was made. In China, however, the development still continues. Czech Republic has almost 60 years nuclear research history and the knowledge of operation of gas cooled and heavy water moderated reactor has been gained in the past. Nevertheless, the design of light water reactors was more developed in former Soviet Union, which provided Czech scientists by initial knowledge base; hence the research has been reoriented to this technology. But, the demands on future nuclear reactors application are still growing and the same or even higher living standard of next generations have to be taken into consideration. Therefore the systems, which can produce more energy and less waste, are getting into foreground of interest of Czech decision makers. The high temperature reactor technology seems to be the successful representative of the GEN IV reactor types, which will be operated commercially in the near future. The broad spectrum of utilization enables this system to be an option after 2030, when the electricity demand is planned to be covered from about 50% by nuclear in our country.

Feasibility study of high temperature reactor utilization in Czech Republic after 2025

International Nuclear Information System (INIS)

Losa, Evžen; Heřmanský, Bedřich; Kobylka, Dušan; Rataj, Jan; Sklenka, Ľubomír; Souček, Václav; Kohout, Petr

2014-01-01

High temperature reactors (HTRs) were examined as an option to intended future broadening of the nuclear energy production in Czech Republic. The known qualities as the inherent safety, high thermal utilization and non-electrical applications have been assessed in years 2009–2011 during the survey funded by Czech Ministry of Industry and Trade. The survey of high temperature reactors with spherical fuel was initiated by reason of mature state of the art of this technology type in South Africa and in China, where in both countries pilot plants were planned. Unfortunately, the global financial crisis caused the decision of stopping the governmental support in South African programme was made. In China, however, the development still continues. Czech Republic has almost 60 years nuclear research history and the knowledge of operation of gas cooled and heavy water moderated reactor has been gained in the past. Nevertheless, the design of light water reactors was more developed in former Soviet Union, which provided Czech scientists by initial knowledge base; hence the research has been reoriented to this technology. But, the demands on future nuclear reactors application are still growing and the same or even higher living standard of next generations have to be taken into consideration. Therefore the systems, which can produce more energy and less waste, are getting into foreground of interest of Czech decision makers. The high temperature reactor technology seems to be the successful representative of the GEN IV reactor types, which will be operated commercially in the near future. The broad spectrum of utilization enables this system to be an option after 2030, when the electricity demand is planned to be covered from about 50% by nuclear in our country

Fuel arrangement for high temperature gas cooled reactor

International Nuclear Information System (INIS)

Tobin, J.M.

1978-01-01

Disclosed is a fuel arrangement for a high temperature gas cooled reactor including fuel assemblies with separate directly cooled fissile and fertile fuel elements removably inserted in an elongated moderator block also having a passageway for control elements

The Integration Of Process Heat Applications To High Temperature Gas Reactors

International Nuclear Information System (INIS)

McKellar, Michael G.

2011-01-01

A high temperature gas reactor, HTGR, can produce industrial process steam, high-temperature heat-transfer gases, and/or electricity. In conventional industrial processes, these products are generated by the combustion of fossil fuels such as coal and natural gas, resulting in significant emissions of greenhouse gases such as carbon dioxide. Heat or electricity produced in an HTGR could be used to supply process heat or electricity to conventional processes without generating any greenhouse gases. Process heat from a reactor needs to be transported by a gas to the industrial process. Two such gases were considered in this study: helium and steam. For this analysis, it was assumed that steam was delivered at 17 MPa and 540 C and helium was delivered at 7 MPa and at a variety of temperatures. The temperature of the gas returning from the industrial process and going to the HTGR must be within certain temperature ranges to maintain the correct reactor inlet temperature for a particular reactor outlet temperature. The returning gas may be below the reactor inlet temperature, ROT, but not above. The optimal return temperature produces the maximum process heat gas flow rate. For steam, the delivered pressure sets an optimal reactor outlet temperature based on the condensation temperature of the steam. ROTs greater than 769.7 C produce no additional advantage for the production of steam.

Development and Evaluation of a Three-Tier Diagnostic Test to Assess Undergraduate Primary Teachers' Understanding of Ecological Footprint

Science.gov (United States)

Liampa, Vasiliki; Malandrakis, George N.; Papadopoulou, Penelope; Pnevmatikos, Dimitrios

2017-08-01

This study focused on the development and validation of a three-tier multiple-choice diagnostic instrument about the ecological footprint. Each question in the three-tier test comprised by; (a) the content tier, assessing content knowledge; (b) the reason tier, assessing explanatory knowledge; and (c) the confidence tier that differentiates lack of knowledge from misconception through the use of a certainty response index. Based on the literature, the propositional knowledge statements and the identified misconceptions of 97 student-teachers, a first version of the test was developed and subsequently administered to another group of 219 student-teachers from Primary and Early Childhood Education Departments. Due to the complexity of the ecological footprint concept, and that it is a newly introduced concept, unknown to the public, both groups have been previously exposed to relevant instruction. Experts in the field established face and content validity. The reliability, in terms of Cronbach's alpha, was found adequate (α = 0.839), and the test-retest reliability, as indicated by Pearson r, was also satisfactory (0.554). The mean performance of the students was 56.24% in total score, 59.75% in content tiers and 48.05% in reason tiers. A variety of concepts about the ecological footprint were also observed. The test can help educators to understand the alternative views that students hold about the ecological footprint concept and assist them in developing the concept through appropriately designed teaching methods and materials.

The Advanced High-Temperature Reactor (AHTR) for Producing Hydrogen to Manufacture Liquid Fuels

International Nuclear Information System (INIS)

Forsberg, C.W.; Peterson, P.F.; Ott, L.

2004-01-01

Conventional world oil production is expected to peak within a decade. Shortfalls in production of liquid fuels (gasoline, diesel, and jet fuel) from conventional oil sources are expected to be offset by increased production of fuels from heavy oils and tar sands that are primarily located in the Western Hemisphere (Canada, Venezuela, the United States, and Mexico). Simultaneously, there is a renewed interest in liquid fuels from biomass, such as alcohol; but, biomass production requires fertilizer. Massive quantities of hydrogen (H2) are required (1) to convert heavy oils and tar sands to liquid fuels and (2) to produce fertilizer for production of biomass that can be converted to liquid fuels. If these liquid fuels are to be used while simultaneously minimizing greenhouse emissions, nonfossil methods for the production of H2 are required. Nuclear energy can be used to produce H2. The most efficient methods to produce H2 from nuclear energy involve thermochemical cycles in which high-temperature heat (700 to 850 C) and water are converted to H2 and oxygen. The peak nuclear reactor fuel and coolant temperatures must be significantly higher than the chemical process temperatures to transport heat from the reactor core to an intermediate heat transfer loop and from the intermediate heat transfer loop to the chemical plant. The reactor temperatures required for H2 production are at the limits of practical engineering materials. A new high-temperature reactor concept is being developed for H2 and electricity production: the Advanced High-Temperature Reactor (AHTR). The fuel is a graphite-matrix, coated-particle fuel, the same type that is used in modular high-temperature gas-cooled reactors (MHTGRs). The coolant is a clean molten fluoride salt with a boiling point near 1400 C. The use of a liquid coolant, rather than helium, reduces peak reactor fuel and coolant temperatures 100 to 200 C relative to those of a MHTGR. Liquids are better heat transfer fluids than gases

An overview of modeling methods for thermal mixing and stratification in large enclosures for reactor safety analysis

Energy Technology Data Exchange (ETDEWEB)

Haihua Zhao; Per F. Peterson

2010-10-01

Thermal mixing and stratification phenomena play major roles in the safety of reactor systems with large enclosures, such as containment safety in current fleet of LWRs, long-term passive containment cooling in Gen III+ plants including AP-1000 and ESBWR, the cold and hot pool mixing in pool type sodium cooled fast reactor systems (SFR), and reactor cavity cooling system behavior in high temperature gas cooled reactors (HTGR), etc. Depending on the fidelity requirement and computational resources, 0-D steady state models (heat transfer correlations), 0-D lumped parameter based transient models, 1-D physical-based coarse grain models, and 3-D CFD models are available. Current major system analysis codes either have no models or only 0-D models for thermal stratification and mixing, which can only give highly approximate results for simple cases. While 3-D CFD methods can be used to analyze simple configurations, these methods require very fine grid resolution to resolve thin substructures such as jets and wall boundaries. Due to prohibitive computational expenses for long transients in very large volumes, 3-D CFD simulations remain impractical for system analyses. For mixing in stably stratified large enclosures, UC Berkeley developed 1-D models basing on Zuber’s hierarchical two-tiered scaling analysis (HTTSA) method where the ambient fluid volume is represented by 1-D transient partial differential equations and substructures such as free or wall jets are modeled with 1-D integral models. This allows very large reductions in computational effort compared to 3-D CFD modeling. This paper will present an overview on important thermal mixing and stratification phenomena in large enclosures for different reactors, major modeling methods and their advantages and limits, potential paths to improve simulation capability and reduce analysis uncertainty in this area for advanced reactor system analysis tools.

Engineering and physics of high-power-density, compact, reversed-field-pinch fusion reactors

International Nuclear Information System (INIS)

Najmabadi, F.; Conn, R.W.; Krakowski, R.A.; Schultz, K.R.; Steiner, D.

1989-01-01

The technical feasibility and key developmental issues of compact, high-power-density Reversed-Field-Pinch (RFP) reactors are the primary results of the TITAN RFP reactor study. Two design approaches emerged, TITAN-I and TITAN-II, both of which are steady-state, DT-burning, circa 1000 MWe power reactors. The TITAN designs are physically compact and have a high neutron wall loading of 18 MW m 2 . Detailed analyses indicate that: a) each design is technically feasible; b) attractive features of compact RFP reactors can be realized without sacrificing the safety and environmental potential of fusion; and c) major features of this particular embodiment of the RFP reactor are retained in a design window of neutron wall loading ranging from 10 to 20 MW/m 2 . A major product of the TITAN study is the identification and quantification of major engineering and physics requirements for this class of RFP reactors. These findings are the focus of this paper. (author). 26 refs.; 4 figs.; 1 tab

Time horizon for AFV emission savings under Tier 2

International Nuclear Information System (INIS)

Saricks, C. L.

2000-01-01

Implementation of the Federal Tier 2 vehicular emission standards according to the schedule presented in the December, 1999 Final Rule will result in substantial reductions of NMHC, CO, NO x , and fine particle emissions from motor vehicles. Currently, when compared to Tier 1 and even NLEV certification requirements, the emissions performance of automobiles and light-duty trucks powered by non-petroleum (especially, gaseous) fuels (i.e., vehicles collectively termed AFVs) enjoy measurable advantage over their gasoline- and diesel-fueled counterparts over the full Federal Test Procedure and, especially, in Bag 1 (cold start). For the lighter end of these vehicle classes, this advantage may disappear shortly after 2004 under the new standards, but should continue for a longer period (perhaps beyond 2008) for the heavier end as well as for heavy-duty vehicles relative to diesel-fueled counterparts. Because of the continuing commitment of the U.S. Department of Energy's Clean Cities coalitions to the acquisition and operation of AFVs of many types and size classes, it is important for them to know in which classes their acquisitions will remain clear relative to the petroleum-fueled counterparts they might otherwise procure. This paper provides an approximate timeline for and expected magnitude of such savings, assuming that full implementation of the Tier 2 standards covering both vehicular emissions and fuel sulfur limits proceeds on schedule. The pollutants of interest are primary ozone precursors and fine particulate matter from fuel combustion

Status of Preconceptual Design of the Advanced High-Temperature Reactor (AHTR)

Energy Technology Data Exchange (ETDEWEB)

Ingersoll, D.T.

2004-07-29

A new reactor plant concept is presented that combines the benefits of ceramic-coated, high-temperature particle fuel with those of clean, high-temperature, low-pressure molten salt coolant. The Advanced High-Temperature Reactor (AHTR) concept is a collaboration of Oak Ridge National Laboratory, Sandia National Laboratories, and the University of California at Berkeley. The purpose of the concept is to provide an advanced design capable of satisfying the top-level functional requirements of the U.S. Department of Energy Next Generation Nuclear Plant (NGNP), while also providing a technology base that is sufficiently robust to allow future development paths to higher temperatures and larger outputs with highly competitive economics. This report summarizes the status of the AHTR preconceptual design. It captures the results from an intense effort over a period of 3 months to (1) screen and examine potential feasibility concerns with the concept; (2) refine the conceptual design of major systems; and (3) identify research, development, and technology requirements to fully mature the AHTR design. Several analyses were performed and are presented to quantify the AHTR performance expectations and to assist in the selection of several design parameters. The AHTR, like other NGNP reactor concepts, uses coated particle fuel in a graphite matrix. But unlike the other NGNP concepts, the AHTR uses molten salt rather than helium as the primary system coolant. The considerable previous experience with molten salts in nuclear environments is discussed, and the status of high-temperature materials is reviewed. The large thermal inertia of the system, the excellent heat transfer and fission product retention characteristics of molten salt, and the low-pressure operation of the primary system provide significant safety attributes for the AHTR. Compared with helium coolant, a molten salt cooled reactor will have significantly lower fuel temperatures (150-200-C lower) for the

Status of Preconceptual Design of the Advanced High-Temperature Reactor (AHTR)

International Nuclear Information System (INIS)

Ingersoll, D.T.

2004-01-01

A new reactor plant concept is presented that combines the benefits of ceramic-coated, high-temperature particle fuel with those of clean, high-temperature, low-pressure molten salt coolant. The Advanced High-Temperature Reactor (AHTR) concept is a collaboration of Oak Ridge National Laboratory, Sandia National Laboratories, and the University of California at Berkeley. The purpose of the concept is to provide an advanced design capable of satisfying the top-level functional requirements of the U.S. Department of Energy Next Generation Nuclear Plant (NGNP), while also providing a technology base that is sufficiently robust to allow future development paths to higher temperatures and larger outputs with highly competitive economics. This report summarizes the status of the AHTR preconceptual design. It captures the results from an intense effort over a period of 3 months to (1) screen and examine potential feasibility concerns with the concept; (2) refine the conceptual design of major systems; and (3) identify research, development, and technology requirements to fully mature the AHTR design. Several analyses were performed and are presented to quantify the AHTR performance expectations and to assist in the selection of several design parameters. The AHTR, like other NGNP reactor concepts, uses coated particle fuel in a graphite matrix. But unlike the other NGNP concepts, the AHTR uses molten salt rather than helium as the primary system coolant. The considerable previous experience with molten salts in nuclear environments is discussed, and the status of high-temperature materials is reviewed. The large thermal inertia of the system, the excellent heat transfer and fission product retention characteristics of molten salt, and the low-pressure operation of the primary system provide significant safety attributes for the AHTR. Compared with helium coolant, a molten salt cooled reactor will have significantly lower fuel temperatures (150-200-C lower) for the

76 FR 48904 - Announcement Regarding the Virgin Islands Triggering “on” Tier Three of Emergency Unemployment...

Science.gov (United States)

2011-08-09

... Islands Triggering ``on'' Tier Three of Emergency Unemployment Compensation 2008 (EUC08). AGENCY... Islands triggering ``on'' Tier Three of Emergency Unemployment Compensation 2008 (EUC08). Public law 111... unemployment states. The Department of Labor produces a trigger notice indicating which states qualify for...

76 FR 14102 - Announcement Regarding the Virgin Islands Triggering “Off” Tier Three of Emergency Unemployment...

Science.gov (United States)

2011-03-15

... Islands Triggering ``Off'' Tier Three of Emergency Unemployment Compensation 2008 (EUC08) AGENCY... Islands triggering ``off'' Tier Three of Emergency Unemployment Compensation 2008 (EUC08). Public Law 111... unemployment states. The Department of Labor produces a trigger notice indicating which states qualify for...

20 CFR 228.40 - Cost of living increase applicable to the tier I annuity component.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Cost of living increase applicable to the... § 228.40 Cost of living increase applicable to the tier I annuity component. The tier I annuity... the Federal Register annually. The cost-of-living increase is payable beginning with the benefit for...

Velocity-Aware Handover Management in Two-Tier Cellular Networks

KAUST Repository

Arshad, Rabe; Elsawy, Hesham; Sorour, Sameh; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

2017-01-01

by network densification. Hence, user mobility imposes a nontrivial challenge to harvest capacity gains via network densification. In this paper, we propose a velocity-aware HO management scheme for two-tier downlink cellular network to mitigate the HO effect

Material and component progress within ARCHER for advanced high temperature reactor

International Nuclear Information System (INIS)

Buckthorpe, D.E.; Davies, M.; Pra, F.; Bonnamy, P.; Fokkens, J.; Heijna, M.; Bout, N. de; Vreeling, A.; Bourlier, F.; Lhachemi, D.; Woayehune, A.; Dubiez-le-Goff, S.; Hahner, P.; Futterer, M.; Berka, J.; Kalivodora, J.; Pouchon, M.A.; Schmitt, R.; Homerin, P.; Marsden, B.; Mummery, P.; Mutch, G.; Ponca, D.; Buhl, P.; Hoffmann, M.; Rondet, F.; Pecherty, A.; Baurand, F.; Alenda, F.; Esch, M.; Kohlz, N.; Reed, J.; Fachinger, J.; Klower, Dr.

2014-01-01

The ARCHER (Advanced High-Temperature Reactors for Cogeneration of Heat and Electricity R and D) integrated project started in 2011 as part of the European Commission 7. Framework Programme (FP7) for a period of four years to perform High Temperature Reactor technology R and D in support of reactor demonstration. The project consortium encompasses conventional and Nuclear Industry, Utilities, Technical Support Organizations, Research and Development Organizations and Academia. The activities involved contribute to the Generation IV (GIF) International Forum and collaborate with related projects in the US, China, Japan, and the Republic of Korea in cooperation with IAEA and ISTC. This paper addresses the progress of the work on materials and component technologies within ARCHER over the first two years of the project. (authors)

PENGGUNAAN KONEKSI CORBA DENGAN PEMROGRAMAN MIDAS MULTI-TIER APPLICATION DALAM SISTEM RESERVASI HOTEL

Directory of Open Access Journals (Sweden)

Irwan Kristanto Julistiono

2001-01-01

Full Text Available This paper is made from a multi-tier system using corba technology for hotel reservation program for web browser and also client program. Client software is connected to application server with Corba Connection and client and application server connect to SQL server 7.0. via ODBC. The are 2 types of client: web client and delphi client. In making web browser client application, we use delphi activex from technology, in where in this system made like making the regular form, but it has shortage in integration with html language. Multi-pier application using corba system generally has another profit beside it could be developed, this system also stake with multi system database server, multi middle servers and multi client in which with these things all the system can system can be integrated. The weakness of this system is the complicated corba system, so it will be difficult to understand, while for multi-tier it self need a particular procedure to determine which server chossed by the client. Abstract in Bahasa Indonesia : Pada makalah ini dibuat suatu sistem multi-tier yang menggunakan teknologi CORBA untuk program reservasi hotel baik dengan web browser maupun program client. Perangkat lunak yang dipakai sebagai database server adalah SQL server 7.0. Program Client Delphi melalui Corba Connection akan dihubungkan ke Aplikasi server. Dan melalui ODBC Aplikasi Server akan dihubungkan ke SQL Server 7.0. Ada dua buah aplikasi client yaitu yang menggunakan lokal network dan yang menggunakan global network/web browser. Pada pembuatan aplikasi client untuk web browser. Digunakan teknologi activex form pada delphi dimana sistem ini dibuat seperti membuat form biasa, hanya saja memiliki kekurangan pada integrasi dengan bahasa html. Penggunaan sistem multi-tier dengan Corba ini secara umum memiliki keuntungan selain dapat dikembangkan lebih lanjut juga sistem ini dirancang dengan sistem multi database server, multi midle server, dan multi client dimana

Engineering safety features for high power experimental reactors

International Nuclear Information System (INIS)

Doval, A.; Villarino, E.; Vertullo, A.

2000-01-01

In the present analysis we will focus our attention in the way engineering safety features are designed in order to prevent fuel damage in case of abnormal or accidental situations. To prevent fuel damage two main facts must be considered, the shutdown of the reactor and the adequate core cooling capacity, it means that both, neutronic and thermohydraulic aspects must be analysed. Some neutronic safety features are common to all power ranges like negative feedback reactivity coefficients and the required number of control rods containing the proper absorber material to shutdown the reactor. From the thermohydraulic point of view common features are siphon-breaker devices and flap valves for those powers requiring cooling in the forced convection regime. For the high power reactor group, the engineering safety features specially designed for a generic reactor of 20 MW, will be presented here. From the neutronic point of view besides the common features, and to comply with our National Regulatory Authority, a Second Shutdown System was designed as a redundant shutdown system in case the control plates fail. Concerning thermohydraulic aspects besides the pump flywheels and the flap valves providing the natural convection loop, a metallic Chimney and a Chimney Water Injection System were supplied. (author)

Features, present condition of development and future scope on the high temperature gas reactor as an innovative one

International Nuclear Information System (INIS)

Shiozawa, Shusaku

2001-01-01

The high temperature gas reactor has some features without previous reactors such as high temperature capable of taking-out, high specific safety, feasibility adaptable to versatile fuel cycle, and so on. Then, it is expected to be an innovative reactor to contribute to diversification of energy supply and expansion of energy application field. In Japan, under the HTTR (high temperature engineering test reactor) plan, construction of HTTR, which is the first high temperature gas reactor in Japan, was finished and its output upgrading test has been promoted. And, on the HTTR plan, together with promotion of full power operation, reactor performance tests, safety proof test, and so on, it is planned to carry out study on application of the high temperature heat such as hydrogen production and so on to aim to practise establishment and upgrading of technologies on high temperature gas reactor in Japan. Here were introduced features and present condition of development of the high temperature gas reactor as an innovative type reactor and described role and future scope in Japan. (G.K.)

Development of a tiered and binned genetic counseling model for informed consent in the era of multiplex testing for cancer susceptibility.

Science.gov (United States)

Bradbury, Angela R; Patrick-Miller, Linda; Long, Jessica; Powers, Jacquelyn; Stopfer, Jill; Forman, Andrea; Rybak, Christina; Mattie, Kristin; Brandt, Amanda; Chambers, Rachelle; Chung, Wendy K; Churpek, Jane; Daly, Mary B; Digiovanni, Laura; Farengo-Clark, Dana; Fetzer, Dominique; Ganschow, Pamela; Grana, Generosa; Gulden, Cassandra; Hall, Michael; Kohler, Lynne; Maxwell, Kara; Merrill, Shana; Montgomery, Susan; Mueller, Rebecca; Nielsen, Sarah; Olopade, Olufunmilayo; Rainey, Kimberly; Seelaus, Christina; Nathanson, Katherine L; Domchek, Susan M

2015-06-01

Multiplex genetic testing, including both moderate- and high-penetrance genes for cancer susceptibility, is associated with greater uncertainty than traditional testing, presenting challenges to informed consent and genetic counseling. We sought to develop a new model for informed consent and genetic counseling for four ongoing studies. Drawing from professional guidelines, literature, conceptual frameworks, and clinical experience, a multidisciplinary group developed a tiered-binned genetic counseling approach proposed to facilitate informed consent and improve outcomes of cancer susceptibility multiplex testing. In this model, tier 1 "indispensable" information is presented to all patients. More specific tier 2 information is provided to support variable informational needs among diverse patient populations. Clinically relevant information is "binned" into groups to minimize information overload, support informed decision making, and facilitate adaptive responses to testing. Seven essential elements of informed consent are provided to address the unique limitations, risks, and uncertainties of multiplex testing. A tiered-binned model for informed consent and genetic counseling has the potential to address the challenges of multiplex testing for cancer susceptibility and to support informed decision making and adaptive responses to testing. Future prospective studies including patient-reported outcomes are needed to inform how to best incorporate multiplex testing for cancer susceptibility into clinical practice.Genet Med 17 6, 485-492.

Upgrading and modernization of the high flux reactor Petten

International Nuclear Information System (INIS)

Ahlf, J.

1992-01-01

The High Flux Reactor (HFR) at Petten, The Netherlands, owned by the European Communities and operated by the Netherlands Energy Research Foundation, is a water-cooled and moderated, multipurpose research reactor of the closed-tank in-pool type, operated at 45 MW. Performance upgrading comprised two power increases from 20 MW via 30 MW to 45 MW, providing more and higher rated irradiation positions in the tank. With the replacement of the original reactor vessel the experimental capabilities of the reactor were improved. Better pool side facilities and the introduction of a large cross-section, double, beam tube were implemented. Additional major installation upgrading activities consisted of the replacement of the primary and the pool heat exchangers, replacement of the beryllium reflector elements, extension of the overpower protection systems and upgrading of the nuclear instrumentation as well as the guaranteed power supply. Control room upgrading is in progress. A full new safety analysis, as well as the introduction of a comprehensive Quality Assurance system, are summarized under software upgrading. Continuous modernization and upgrading also takes place of equipment for fuel and structural materials irradiations for fission reactors and future fusion machines. In parallel, all supporting services, as well as the management structure for large irradiation programmes, have been developed. Presently the reactor is operating at about 275 full power days per year with an average utilization of the irradiation positions of 70 to 80%. (orig.)

Development and Application of a Two-Tier Multiple-Choice Diagnostic Test for High School Students' Understanding of Cell Division and Reproduction

Science.gov (United States)

Sesli, Ertugrul; Kara, Yilmaz

2012-01-01

This study involved the development and application of a two-tier diagnostic test for measuring students' understanding of cell division and reproduction. The instrument development procedure had three general steps: defining the content boundaries of the test, collecting information on students' misconceptions, and instrument development.…

Aftertreatment in a pre-turbocharger position. Size and fuel consumption advantage for Tier 4

Energy Technology Data Exchange (ETDEWEB)

Bruestle, Claus [Emitec, Inc., Rochester Hills, MI (United States); Tomazic, Dean; Franke, Michael [FEV, Inc., Auburn Hills, MI (United States)

2013-05-15

As the 2014 implementation of EPA Tier 4 fast approaches in the US A, manufacturers of large bore diesel engines face a dilemma. The stringent limits set by Tier 4 legislation require large, heavy and expensive emissions control systems but severe constraints on installation space, weight and cost exist for these systems. A viable solution is to place catalysts and filters upstream of the turbocharger. (orig.)

Design of multi-tiered database application based on CORBA component in SDUV-FEL system

International Nuclear Information System (INIS)

Sun Xiaoying; Shen Liren; Dai Zhimin

2004-01-01

The drawback of usual two-tiered database architecture was analyzed and the Shanghai Deep Ultraviolet-Free Electron Laser database system under development was discussed. A project for realizing the multi-tiered database architecture based on common object request broker architecture (CORBA) component and middleware model constructed by C++ was presented. A magnet database was given to exhibit the design of the CORBA component. (authors)

Examining the Efficacy of a Tier 2 Kindergarten Mathematics Intervention.

Science.gov (United States)

Clarke, Ben; Doabler, Christian T; Smolkowski, Keith; Baker, Scott K; Fien, Hank; Strand Cary, Mari

2016-01-01

This study examined the efficacy of a Tier 2 kindergarten mathematics intervention program, ROOTS, focused on developing whole number understanding for students at risk in mathematics. A total of 29 classrooms were randomly assigned to treatment (ROOTS) or control (standard district practices) conditions. Measures of mathematics achievement were collected at pretest and posttest. Treatment and control students did not differ on mathematics assessments at pretest. Gain scores of at-risk intervention students were significantly greater than those of control peers, and the gains of at-risk treatment students were greater than the gains of peers not at risk, effectively reducing the achievement gap. Implications for Tier 2 mathematics instruction in a response to intervention (RtI) model are discussed. © Hammill Institute on Disabilities 2014.

Proposed high throughput electrorefining treatment for spent N- Reactor fuel

International Nuclear Information System (INIS)

Gay, E.C.; Miller, W.E.; Laidler, J.J.

1996-01-01

A high-throughput electrorefining process is being adapted to treat spent N-Reactor fuel for ultimate disposal in a geologic repository. Anodic dissolution tests were made with unirradiated N-Reactor fuel to determine the type of fragmentation necessary to provide fuel segments suitable for this process. Based on these tests, a conceptual design was produced of a plant-scale electrorefiner. In this design, the diameter of an electrode assembly is about 1.07 m (42 in.). Three of these assemblies in an electrorefiner would accommodate a 3-metric-ton batch of N-Reactor fuel that would be processed at a rate of 42 kg of uranium per hour

Pressurizer pump reliability analysis high flux isotope reactor

International Nuclear Information System (INIS)

Merryman, L.; Christie, B.

1993-01-01

During a prolonged outage from November 1986 to May 1990, numerous changes were made at the High Flux Isotope Reactor (HFIR). Some of these changes involved the pressurizer pumps. An analysis was performed to calculate the impact of these changes on the pressurizer system availability. The analysis showed that the availability of the pressurizer system dropped from essentially 100% to approximately 96%. The primary reason for the decrease in availability comes because off-site power grid disturbances sometimes result in a reactor trip with the present pressurizer pump configuration. Changes are being made to the present pressurizer pump configuration to regain some of the lost availability

Theoretical multi-tier trust framework for the geospatial domain

CSIR Research Space (South Africa)

Umuhoza, D

2010-01-01

Full Text Available chain or workflow from data acquisition to knowledge discovery. The author’s present work in progress of a theoretical multi-tier trust framework for processing chain from data acquisition to knowledge discovery in geospatial domain. Holistic trust...

VM-based infrastructure for simulating different cluster and storage solutions used on ATLAS Tier-3 sites

International Nuclear Information System (INIS)

Belov, S; Kadochnikov, I; Korenkov, V; Kutouski, M; Oleynik, D; Petrosyan, A

2012-01-01

The current ATLAS Tier-3 infrastructure consists of a variety of sites of different sizes and with a mix of local resource management systems (LRMS) and mass storage system (MSS) implementations. The Tier-3 monitoring suite, having been developed in order to satisfy the needs of Tier-3 site administrators and to aggregate Tier-3 monitoring information on the global VO level, needs to be validated for various combinations of LRMS and MSS solutions along with the corresponding Ganglia plugins. For this purpose the testbed infrastructure, which allows simulation of various computational cluster and storage solutions, had been set up at JINR (Dubna, Russia). This infrastructure provides the ability to run testbeds with various LRMS and MSS implementations, and with the capability to quickly redeploy particular testbeds or their components. Performance of specific components is not a critical issue for development and validation, whereas easy management and deployment are crucial. Therefore virtual machines were chosen for implementation of the validation infrastructure which, though initially developed for Tier-3 monitoring project, can be exploited for other purposes. Load generators for simulation of the computing activities at the farm were developed as a part of this task. The paper will cover concrete implementation, including deployment scenarios, hypervisor details and load simulators.

High Flux Materials Testing Reactor (HFR), Petten

International Nuclear Information System (INIS)

1975-09-01

After conversion to burnable poison fuel elements, the High Flux Materials Testing Reactor (HFR) Petten (Netherlands), operated through 1974 for 280 days at 45 MW. Equipment for irradiation experiments has been replaced and extended. The average annual occupation by experiments was 55% as compared to 38% in 1973. Work continued on thirty irradiation projects and ten development activities

Safety Philosophy in Process Heat Plants Coupled to High Temperature Reactors

International Nuclear Information System (INIS)

Brown, Nicholas R.; Revankar, Shripad T.

2011-01-01

With the future availability of fossil fuel resources in doubt, high temperature nuclear reactors have the potential to be an important technology in the near term. Due to a high coolant outlet temperature, high temperature reactors (HTR) can be used to drive chemical plants that directly utilize process heat. Additionally, the high temperature improves the thermodynamic efficiency of the energy utilization. Many applications of high temperature reactors exist as a thermal driving vector for endothermic chemical process plants. Hydrogen generation using the General Atomics (GA) sulfur iodine (SI) cycle is one promising application of high temperature nuclear heat. The main chemical reactions in the SI cycle are: 1. I 2 +SO 2 + 2H 2 O → 2HI + H 2 SO 4 (Bunsen reaction) 2. H 2 SO 4 → H 2 O + SO 2 + 1/2O 2 (Sulfuric acid decomposition) 3. 2HI → H 2 + I 2 (Hydrogen Iodide decomposition). With the exception of hydrogen and oxygen, all relevant reactants are recycled within the process. However, there are many unresolved safety and operational issues related to implementation of such a coupled plant

Programmes and projects for high-temperature reactor development

International Nuclear Information System (INIS)

Bogusch, Edgar; Hittner, Dominique

2009-01-01

An increasing attention has to be recognised worldwide on the development of High-Temperature Reactors (HTR) which has started in Germany and other countries in the 1970ies. While pebble bed reactors with spherical fuel elements have been developed and constructed in Germany, countries such as France, the US and Russia investigated HTR concepts with prismatic block-type fuel elements. The concept of a modular HTR formerly developed by Areva NP was an essential basis for the HTR-10 in China. A pebble bed HTR for electricity production is developed in South Africa. The construction is planned after the completion of the licensing procedure. Also the US is planning an HTR under the NGNP (Next Generation Nuclear Plant) Project. Due to the high temperature level of the helium coolant, the HTR can be used not only for electricity production but also for supply of process heat. Including its inherent safety features the HTR is an attractive candidate for heat supply to various types of plants e.g. for hydrogen production or coal liquefactions. The conceptual design of an HTR with prismatic fuel elements for the cogeneration of electricity and process heat has been developed by Areva NP. On the European scale the HTR development is promoted by the RAPHAEL (ReActor for Process heat, Hydrogen And ELectricity generation) project. RAPHAEL is an Integrated Project of the Euratom 6th Framework Programme for the development of technologies towards a Very High-Temperature Reactor (VHTR) for the production of electricity and heat. It is financed jointly by the European Commission and the partners of the HTR Technology Network (HTR-TN) and coordinated by Areva NP. The RAPHAEL project not only promotes HTR development but also the cooperation with other European projects such as the material programme EXTREMAT. Furthermore HTR technology is investigated in the frame of Generation IV International Forum (GIF). The development of a VHTR with helium temperatures above 900 C for the

Monte Carlo Analysis of the Battery-Type High Temperature Gas Cooled Reactor

Science.gov (United States)

Grodzki, Marcin; Darnowski, Piotr; Niewiński, Grzegorz

2017-12-01

The paper presents a neutronic analysis of the battery-type 20 MWth high-temperature gas cooled reactor. The developed reactor model is based on the publicly available data being an `early design' variant of the U-battery. The investigated core is a battery type small modular reactor, graphite moderated, uranium fueled, prismatic, helium cooled high-temperature gas cooled reactor with graphite reflector. The two core alternative designs were investigated. The first has a central reflector and 30×4 prismatic fuel blocks and the second has no central reflector and 37×4 blocks. The SERPENT Monte Carlo reactor physics computer code, with ENDF and JEFF nuclear data libraries, was applied. Several nuclear design static criticality calculations were performed and compared with available reference results. The analysis covered the single assembly models and full core simulations for two geometry models: homogenous and heterogenous (explicit). A sensitivity analysis of the reflector graphite density was performed. An acceptable agreement between calculations and reference design was obtained. All calculations were performed for the fresh core state.

Monte Carlo Analysis of the Battery-Type High Temperature Gas Cooled Reactor

Directory of Open Access Journals (Sweden)

Grodzki Marcin

2017-12-01

Full Text Available The paper presents a neutronic analysis of the battery-type 20 MWth high-temperature gas cooled reactor. The developed reactor model is based on the publicly available data being an ‘early design’ variant of the U-battery. The investigated core is a battery type small modular reactor, graphite moderated, uranium fueled, prismatic, helium cooled high-temperature gas cooled reactor with graphite reflector. The two core alternative designs were investigated. The first has a central reflector and 30×4 prismatic fuel blocks and the second has no central reflector and 37×4 blocks. The SERPENT Monte Carlo reactor physics computer code, with ENDF and JEFF nuclear data libraries, was applied. Several nuclear design static criticality calculations were performed and compared with available reference results. The analysis covered the single assembly models and full core simulations for two geometry models: homogenous and heterogenous (explicit. A sensitivity analysis of the reflector graphite density was performed. An acceptable agreement between calculations and reference design was obtained. All calculations were performed for the fresh core state.

First conceptual design of the experimental multi-purpose high temperature reactor

Energy Technology Data Exchange (ETDEWEB)

Tsunoda, T [Fuji Electric Co. Ltd., Tokyo (Japan)

1976-02-01

A part of the multi-purpose high temperature reactor (VHTR) was designed by the First Atomic Power Industry Group (FAPIG). Both Fuji Electric Co., Ltd. and Kawasaki Heavy Industries, Ltd. of the FAPIG group took charge of the design of main parts of the reactor Kobe Steel, Ltd., Ebara Manufacturing Co., Ltd., Shimizu Construction Co., Ltd. and the Nuclear Fuel Corp. have associated with this group. The reactor system includes a nuclear reactor and two cooling loops provided through intermediate heat exchangers in order to utilize the heat of helium gas delivered from the reactor outlet at 1,000 deg C. One is a reformer loop to produce the reducing gas for steel manufacture. The other is a testing loop for a reducing gas heater and a gas turbine. These loops transfer heat of about 25 MW at 930 deg C at rated capacity. The reformer can supply the reducing gas equivalent to the production of 100 tons per day sponge iron. A housing of the reactor is composed of a primary steel container, internal concrete and a secondary container made of reinforced concrete. The construction is based on the following principles. (1) For the very high temperature portion at 1,000 deg C, a non-metallic material such as graphite should be used. (2) The metallic construction shall be cooled with return gas below 400 deg C. (3) The steel pressure vessel shall be employed. (4) The design shall be based on the existing gas furnace.

Global scaling analysis for the pebble bed advanced high temperature reactor

International Nuclear Information System (INIS)

Blandford, E.D.; Peterson, P.F.

2009-01-01

Scaled Integral Effects Test (IET) facilities play a critical role in the design certification process of innovative reactor designs. Best-estimate system analysis codes, which minimize deliberate conservatism, require confirmatory data during the validation process to ensure an acceptable level of accuracy as defined by the regulator. The modular Pebble Bed Advanced High Temperature Reactor (PB-AHTR), with a nominal power output of 900 MWth, is the most recent UC Berkeley design for a liquid fluoride salt cooled, solid fuel reactor. The PB-AHTR takes advantage of technologies developed for gas-cooled high temperature thermal and fast reactors, sodium fast reactors, and molten salt reactors. In this paper, non-dimensional scaling groups and similarity criteria are presented at the global system level for a loss of forced circulation transient, where single-phase natural circulation is the primary mechanism for decay heat removal following a primary pump trip. Due to very large margin to fuel damage temperatures, the peak metal temperature of primary-loop components was identified as the key safety parameter of interest. Fractional Scaling Analysis (FSA) methods were used to quantify the intensity of each transfer process during the transient and subsequently rank them by their relative importance while identifying key sources of distortion between the prototype and model. The results show that the development of a scaling hierarchy at the global system level informs the bottom-up scaling analysis. (author)

Transporting Motivational Interviewing to School Settings to Improve the Engagement and Fidelity of Tier 2 Interventions

Science.gov (United States)

Frey, Andy J.; Lee, Jon; Small, Jason W.; Seeley, John R.; Walker, Hill M.; Feil, Edward G.

2013-01-01

The majority of Tier 2 interventions are facilitated by specialized instructional support personnel, such as a school psychologists, school social workers, school counselors, or behavior consultants. Many professionals struggle to involve parents and teachers in Tier 2 behavior interventions. However, attention to the motivational issues for…

OECD high temperature reactor project Dragon

International Nuclear Information System (INIS)

1975-01-01

Information is presented concerning the Dragon reactor support studies and fuel irradiation programs, HTGR and fuel graphite studies, primary circuit materials, reactor safety evaluation, and administration

Concept of an inherently-safe high temperature gas-cooled reactor

International Nuclear Information System (INIS)

Ohashi, Hirofumi; Sato, Hiroyuki; Tachibana, Yukio; Kunitomi, Kazuhiko; Ogawa, Masuro

2012-01-01

As the challenge to ensure no harmful release of radioactive materials at the accidents by deterministic approach instead to satisfy acceptance criteria or safety goal for risk by probabilistic approach, new concept of advanced reactor, an inherently-safe high temperature gas-cooled reactor, is proposed based on the experience of the operation of the actual High Temperature Gas-cooled Reactor (HTGR) in Japan, High Temperature Engineering Test Reactor (HTTR), and the design of the commercial plant (GTHTR300), utilizing the inherent safety features of the HTGR (i.e., safety features based on physical phenomena). The safety design philosophy of the inherently-safe HTGR for the safety analysis of the radiological consequences is determined as the confinement of radioactive materials is assured by only inherent safety features without engineered safety features, AC power or prompt actions by plant personnel if the design extension conditions occur. Inherent safety features to prevent the loss or degradation of the confinement function are identified. It is proposed not to apply the probabilistic approach for the evaluation of the radiological consequences of the accidents in the safety analysis because no inherent safety features fail for the mitigation of the consequences of the accidents. Consequently, there are no event sequences to harmful release of radioactive materials if the design extension conditions occur in the inherently-safe HTGR concept. The concept and future R and D items for the inherently-safe HTGR are described in this paper.

A procedure validation for high conversion reactors fuel elements calculation

International Nuclear Information System (INIS)

Ishida, V.N.; Patino, N.E.; Abbate, M.J.; Sbaffoni, M.M.

1990-01-01

The present work includes procedure validation of cross sections generation starting from nuclear data and the calculation system actually used at the Bariloche Atomic Center Reactor and Neutrons Division for its application to fuel elements calculation of a high conversion reactor (HCR). To this purpose, the fuel element calculation belonging to a High Conversion Boiling water Reactor (HCBWR) was chosen as reference problem, employing the Monte Carlo method. Various cases were considered: with and without control bars, cold of hot, at different vacuum fractions. Multiplication factors, reaction rates, power maps and peak factors were compared. A sensitivity analysis of typical cells used, the approximations employed to solve the transport equation (Sn or Diffusion), the 1-D or 2-D representation and densification of the spatial network used, with the aim of evaluating their influence on the parameters studied and to come to an optimum combination to be used in future design calculations. (Author) [es

New temperature monitoring devices for high-temperature irradiation experiments in the high flux reactor Petten

Energy Technology Data Exchange (ETDEWEB)

Laurie, M.; Futterer, M. A.; Lapetite, J. M. [European Commission Joint Research Centre, Institute for Energy, P.O. Box 2, NL-1755 ZG Petten (Netherlands); Fourrez, S. [THERMOCOAX SAS, BP 26, Planquivon, 61438 Flers Cedex (France); Morice, R. [Laboratoire National de Metrologie et d' Essais, 1 rue Gaston Boissier, 75724 Paris (France)

2009-07-01

Within the European High Temperature Reactor Technology Network (HTR-TN) and related projects a number of HTR fuel irradiations are planned in the High Flux Reactor Petten (HFR), The Netherlands, with the objective to explore the potential of recently produced fuel for even higher temperature and burn-up. Irradiating fuel under defined conditions to extremely high burn-ups will provide a better understanding of fission product release and failure mechanisms if particle failure occurs. After an overview of the irradiation rigs used in the HFR, this paper sums up data collected from previous irradiation tests in terms of thermocouple data. Some research and development work for further improvement of thermocouples and other on-line instrumentation will be outlined. (authors)

A TSTT integrated FronTier code and its applications in computational fluid physics

International Nuclear Information System (INIS)

Fix, Brian; Glimm, James; Li Xiaolin; Li Yuanhua; Liu Xinfeng; Samulyak, Roman; Xu Zhiliang

2005-01-01

We introduce the FronTier-Lite software package and its adaptation to the TSTT geometry and mesh entity data interface. This package is extracted from the original front tracking code for general purpose scientific and engineering applications. The package contains a static interface library and a dynamic front propagation library. It can be used in research of different scientific problems. We demonstrate the application of FronTier in the simulations of fuel injection jet, the fusion pellet injection and fluid mixing problems

Investigations of anticipated transients without scram (ATWS) for the high temperature reactor

International Nuclear Information System (INIS)

Heckhoff, H.D.

1981-10-01

In this study anticipated transients without scram (ATWS) are investigated for the high temperature reactor, especially for the thorium high temperature reactor (THTR) 300 MWe as an example. It is shown that the two ATWS 'feedwater flow reduction from full power' and 'positive reactivity insertion of 1 mNile/s from 40 per cent power' are the most important transients for the THTR. The additional load caused by the ATWS can be reduced sufficiently by some small modifications of the afterheat removal system. Supplementary precautions are not necessary. In the last part of this study some possibilities to improve the behaviour of the power plant are shown with regard to high temperature reactors of the future, the partial scram as well as some modifications of heating and cooling of the steam generator. (orig.) [de

High converter pressurized water reactor with heavy water as a coolant

International Nuclear Information System (INIS)

Ronen, Y.; Reyev, D.

1983-01-01

There is an increasing interest in water breeder and high converter reactors. The increase in the conversion ratio of these reactors is obtained by hardening the neutron spectrum achieved by tightening the reactor's lattice. Another way of hardening the neutron spectrum is to replace the light water with heavy water. Two pressurized water reactor fuel cycles that use heavy water as a coolant are considered. The first fuel cycle is based on plutonium and depleted uranium, and the second cycle is based on plutonium and enriched uranium. The uranium ore and separative work unit (SWU) requirements are calculated as well as the fuel cycle cost. The savings in uranium ore are about40 and 60% and about40% in SWU for both fuel cycles considered

76 FR 21422 - Notice To Rescind a Notice of Intent to Prepare a Tiered Environmental Impact Statement

Science.gov (United States)

2011-04-15

... to Prepare a Tiered Environmental Impact Statement AGENCY: Federal Highway Administration (FHWA), DOT. ACTION: Notice to Rescind a Notice of Intent to Prepare a Tiered Environmental Impact Statement. SUMMARY... Heitmann, Environmental Specialist, Federal Highway Administration, New Mexico Division Office, 4001 Office...

A Multi-Tier Social-Ecological System Analysis of Protected Areas Co-Management in Belize

Directory of Open Access Journals (Sweden)

Kenrick W. Williams

2016-01-01

Full Text Available Co-management of protected areas has been recognized as a viable option to sustainably manage ecosystems. This collaborative approach actively engages civil society in the protected areas governance processes. Attempts at co-management, however, have not been uniformly successful; whereas the governance of some initiatives succeed and become strong and sustainable, others become weak or fail over time. In this paper, we provide a nuanced application of Ostrom’s multi-tier SES framework to carry out a systematic analysis of representative cases of co-management in Belize. This novel approach allows us to avoid the common problem of overstating the explanatory power of individual variables, while enabling us to tease out the interrelationships among critical process and contextual variables that may influence co-management outcomes. Our findings show that strong co-management is associated with a multiplicity of variables, including information sharing, conflict resolution, investments, self-organization, and networking. Contextual conditions inclusive of strong leadership, social capital, and high levels of dependence on resources for daily livelihoods seem to have influenced these processes over time. The presence of cross-scale and cross-level networks also seems to be important in influencing co-management outcomes. Our study contributes to the further development of Ostrom’s multi-tier SES framework by proposing the addition of five new third-tier variables. We advance some key lessons in the analysis of co-management outcomes and offer some policy recommendations to improve protected areas co-management policy and practice in Belize.

Nuclear design for high temperature gas cooled reactor (GTHTR300C) using MOX fuel

International Nuclear Information System (INIS)

Mouri, Tomoaki; Kunitomi, Kazuhiko

2008-01-01

A design study of the hydrogen cogeneration high temperature gas cooled reactor (GTHTR300C) that can produce both electricity and hydrogen has been carried out in Japan Atomic Energy Agency. The GTHTR300C is the system with thermal power of 600MW and reactor outlet temperature of 950degC, which is expected to supply the hydrogen to fuel cell vehicles after 2020s. In future, the full deployment of fast reactor cycle without natural uranium will demand the use of Mixed-Oxide (MOX) fuels in the GTHTR300C. Therefore, a nuclear design was performed to confirm the feasibility of the reactor core using MOX fuels. The designed reactor core has high performance and meets safety requirements. In this paper, the outline of the GTHTR300C and the nuclear design of the reactor core using MOX fuels are described. (author)

Application of high strength steel to nuclear reactor containment vessel

International Nuclear Information System (INIS)

Susukida, H.; Sato, M.; Takano, G.; Uebayashi, T.; Yoshida, K.

1976-01-01

Nuclear reactor containment vessels are becoming larger in size with the increase in the power generating capacity of nuclear power plants. For example, a containment vessel for a PWR power plant with an output of 1,000 MWe becomes an extremely large one if it is made of the conventional JIS SGV 49 (ASTM A 516 Gr. 70) steel plates less than 38 mm in thickness. In order to design the steel containment vessel within the conventional dimensional range, therefore, it is necessary to use a high strength steel having a higher tensile strength than SGV 49 steel, good weldability and a higher fracture toughness and moreover, possessing satisfactory properties without undergoing post-weld heat treatment. The authors conducted a series of verification tests on high strength steel developed by modifying the ASTM A 543 Grade B Class 1 steel with a view to adopting it as a material for the nuclear reactor containment vessels. As the result of evaluation of the test results from various angles, we confirmed that the high strength steel is quite suitable for the manufacture of nuclear reactor containment vessels. (auth.)

Design concepts and status of the Korean next generation reactor (KNGR)

International Nuclear Information System (INIS)

Cho, Sung Jae; Kim, Han Gon

1999-01-01

The national project to develop KNGR, a 4000 MWth evolutionary advanced light water reactor (ALWR), has been organized in three phases according to the development status in 1992. During the first phase, the top-tier design requirements and the design concepts to meet the requirements had been established. The project is currently in the second phase of which the major objective is to complete the basic design sufficient to confirm the plant safety. This paper describes the overall design concepts and status of the KNGR briefly which developed and/or being developed through the project. (author)

Advanced High-Temperature Reactor Dynamic System Model Development: April 2012 Status

Energy Technology Data Exchange (ETDEWEB)

Qualls, A L; Cetiner, M S; Wilson, Jr, T L

2012-04-30

The Advanced High-Temperature Reactor (AHTR) is a large-output fluoride-salt-cooled high-temperature reactor (FHR). An early-phase preconceptual design of a 1500 MW(e) power plant was developed in 2011 [Refs. 1 and 2]. An updated version of this plant is shown as Fig. 1. FHRs feature low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. The AHTR is designed to be a “walk away” reactor that requires no action to prevent large off-site releases following even severe reactor accidents. This report describes the development of dynamic system models used to further the AHTR design toward that goal. These models predict system response during warmup, startup, normal operation, and limited off-normal operating conditions. Severe accidents that include a loss-of-fluid inventory are not currently modeled. The scope of the models is limited to the plant power system, including the reactor, the primary and intermediate heat transport systems, the power conversion system, and safety-related or auxiliary heat removal systems. The primary coolant system, the intermediate heat transport system and the reactor building structure surrounding them are shown in Fig. 2. These systems are modeled in the most detail because the passive interaction of the primary system with the surrounding structure and heat removal systems, and ultimately the environment, protects the reactor fuel and the vessel from damage during severe reactor transients. The reactor silo also plays an important role during system warmup. The dynamic system modeling tools predict system performance and response. The goal is to accurately predict temperatures and pressures within the primary, intermediate, and power conversion systems and to study the impacts of design changes on those responses. The models are design tools and are not intended to be used in reactor qualification. The important details to capture in the primary

Assessing the Nutritional Quality of Diets of Canadian Adults Using the 2014 Health Canada Surveillance Tool Tier System

Directory of Open Access Journals (Sweden)

Mahsa Jessri

2015-12-01

Full Text Available The 2014 Health Canada Surveillance Tool (HCST was developed to assess adherence of dietary intakes with Canada’s Food Guide. HCST classifies foods into one of four Tiers based on thresholds for sodium, total fat, saturated fat and sugar, with Tier 1 representing the healthiest and Tier 4 foods being the unhealthiest. This study presents the first application of HCST to assess (a dietary patterns of Canadians; and (b applicability of this tool as a measure of diet quality among 19,912 adult participants of Canadian Community Health Survey 2.2. Findings indicated that even though most of processed meats and potatoes were Tier 4, the majority of reported foods in general were categorized as Tiers 2 and 3 due to the adjustable lenient criteria used in HCST. Moving from the 1st to the 4th quartile of Tier 4 and “other” foods/beverages, there was a significant trend towards increased calories (1876 kcal vs. 2290 kcal and “harmful” nutrients (e.g., sodium as well as decreased “beneficial” nutrients. Compliance with the HCST was not associated with lower body mass index. Future nutrient profiling systems need to incorporate both “positive” and “negative” nutrients, an overall score and a wider range of nutrient thresholds to better capture food product differences.

Spanish ATLAS Tier-2 facing up to Run-2 period of LHC

CERN Document Server

Gonzalez de la Hoz, Santiago; The ATLAS collaboration; Fassi, Farida; Fernandez Casani, Alvaro; Kaci, Mohammed; Lacort Pellicer, Victor Ruben; Montiel Gonzalez, Almudena Del Rocio; Oliver Garcia, Elena; Pacheco Pages, Andres; Salt, José; Villaplana Perez, Miguel; Sanchez Martinez, Victoria; Sánchez, Javier

2015-01-01

The goal of this work is to describe the way of addressing the main challenges of Run-2 by the Spanish ATLAS Tier-2. The considerable increase of energy and luminosity for the upcoming Run-2 w.r.t. Run-1 has led to a revision of the ATLAS computing model as well as some of the main ATLAS computing tools. The adaptation to these changes will be shown, with the peculiarities that it is a distributed Tier-2 composed of three sites and its members are involved on ATLAS computing tasks with a hub of research, innovation and education.

Design and Implementation of an Embedded NIOS II System for JPEG2000 Tier II Encoding

Directory of Open Access Journals (Sweden)

John M. McNichols

2013-01-01

Full Text Available This paper presents a novel implementation of the JPEG2000 standard as a system on a chip (SoC. While most of the research in this field centers on acceleration of the EBCOT Tier I encoder, this work focuses on an embedded solution for EBCOT Tier II. Specifically, this paper proposes using an embedded softcore processor to perform Tier II processing as the back end of an encoding pipeline. The Altera NIOS II processor is chosen for the implementation and is coupled with existing embedded processing modules to realize a fully embedded JPEG2000 encoder. The design is synthesized on a Stratix IV FPGA and is shown to out perform other comparable SoC implementations by 39% in computation time.

Decommissioning of the High Flux Beam Reactor at Brookhaven National Laboratory.

Science.gov (United States)

Hu, Jih-Perng; Reciniello, Richard N; Holden, Norman E

2012-08-01

The High Flux Beam Reactor (HFBR) at the Brookhaven National Laboratory was a heavy-water cooled and moderated reactor that achieved criticality on 31 October 1965. It operated at a power level of 40 mega-watts. An equipment upgrade in 1982 allowed operations at 60 mega-watts. After a 1989 reactor shutdown to reanalyze safety impact of a hypothetical loss of coolant accident, the reactor was restarted in 1991 at 30 mega-watts. The HFBR was shut down in December 1996 for routine maintenance and refueling. At that time, a leak of tritiated water was identified by routine sampling of ground water from wells located adjacent to the reactor's spent fuel pool. The reactor remained shut down for almost 3 y for safety and environmental reviews. In November 1999, the United States Department of Energy decided to permanently shut down the HFBR. The decontamination and decommissioning of the HFBR complex, consisting of multiple structures and systems to operate and maintain the reactor, were complete in 2009 after removing and shipping off all the control rod blades. The emptied and cleaned HFBR dome, which still contains the irradiated reactor vessel is presently under 24/7 surveillance for safety. Details of the HFBR's cleanup performed during 1999-2009, to allow the BNL facilities to be re-accessed by the public, will be described in the paper.

Operating manual for the High Flux Isotope Reactor. Description of the facility

Energy Technology Data Exchange (ETDEWEB)

None

1965-06-01

This report contains a comprehensive description of the High Flux Isotope Reactor facility. Its primary purpose is to supplement the detailed operating procedures, providing the reactor operators with background information on the various HFIR systems. The detailed operating procedures are presented in another report.

Research on reactor physics using the Very High Temperature Reactor Critical Assembly (VHTRC)

International Nuclear Information System (INIS)

Akino, Fujiyoshi

1988-01-01

The High Temperature Engineering Test Reactor (HTTR), of which the research and development are advanced by Japan Atomic Energy Research Institute, is planned to apply for the permission of installation in fiscal year 1988, and to start the construction in the latter half of fisical year 1989. As the duty of reactor physics research, the accuracy of the nuclear data is to be confirmed, the validity of the nuclear design techniques is to be inspected, and the nuclear safety of the HTTR core design is to be verified. Therefore, by using the VHTRC, the experimental data of the reactor physics quantities are acquired, such as critical mass, the reactivity worth of simulated control rods and burnable poison rods, the temperature factor of reactivity, power distribution and so on, and the experiment and analysis are advanced. The cores built up in the VHTRC so far were three kinds having different lattice forms and degrees of uranium enrichment. The calculated critical mass was smaller by 1-5 % than the measured values. As to the power distribution and the reactivity worth of burnable poison rods, the prospect of satisfying the required accuracy for the design of the HTTR core was obtained. The experiment using a new core having axially different enrichment degree is planned. (K.I.)

High power ring methods and accelerator driven subcritical reactor application

Energy Technology Data Exchange (ETDEWEB)

Tahar, Malek Haj [Univ. of Grenoble (France)

2016-08-07

High power proton accelerators allow providing, by spallation reaction, the neutron fluxes necessary in the synthesis of fissile material, starting from Uranium 238 or Thorium 232. This is the basis of the concept of sub-critical operation of a reactor, for energy production or nuclear waste transmutation, with the objective of achieving cleaner, safer and more efficient process than today’s technologies allow. Designing, building and operating a proton accelerator in the 500-1000 MeV energy range, CW regime, MW power class still remains a challenge nowadays. There is a limited number of installations at present achieving beam characteristics in that class, e.g., PSI in Villigen, 590 MeV CW beam from a cyclotron, SNS in Oakland, 1 GeV pulsed beam from a linear accelerator, in addition to projects as the ESS in Europe, a 5 MW beam from a linear accelerator. Furthermore, coupling an accelerator to a sub-critical nuclear reactor is a challenging proposition: some of the key issues/requirements are the design of a spallation target to withstand high power densities as well as ensure the safety of the installation. These two domains are the grounds of the PhD work: the focus is on the high power ring methods in the frame of the KURRI FFAG collaboration in Japan: upgrade of the installation towards high intensity is crucial to demonstrate the high beam power capability of FFAG. Thus, modeling of the beam dynamics and benchmarking of different codes was undertaken to validate the simulation results. Experimental results revealed some major losses that need to be understood and eventually overcome. By developing analytical models that account for the field defects, one identified major sources of imperfection in the design of scaling FFAG that explain the important tune variations resulting in the crossing of several betatron resonances. A new formula is derived to compute the tunes and properties established that characterize the effect of the field imperfections on the

Fusion reactors-high temperature electrolysis (HTE)

International Nuclear Information System (INIS)

Fillo, J.A.

1978-01-01

Results of a study to identify and develop a reference design for synfuel production based on fusion reactors are given. The most promising option for hydrogen production was high-temperature electrolysis (HTE). The main findings of this study are: 1. HTE has the highest potential efficiency for production of synfuels from fusion; a fusion to hydrogen energy efficiency of about 70% appears possible with 1800 0 C HTE units and 60% power cycle efficiency; an efficiency of about 50% possible with 1400 0 C HTE units and 40% power cycle efficiency. 2. Relative to thermochemical or direct decomposition methods HTE technology is in a more advanced state of development, 3. Thermochemical or direct decomposition methods must have lower unit process or capital costs if they are to be more attractive than HTE. 4. While design efforts are required, HTE units offer the potential to be quickly run in reverse as fuel cells to produce electricity for restart of Tokamaks and/or provide spinning reserve for a grid system. 5. Because of the short timescale of the study, no detailed economic evaluation could be carried out.A comparison of costs could be made by employing certain assumptions. For example, if the fusion reactor-electrolyzer capital installation is $400/(KW(T) [$1000/KW(E) equivalent], the H 2 energy production cost for a high efficiency (about 70 %) fusion-HTE system is on the same order of magnitude as a coal based SNG plant based on 1976 dollars. 6. The present reference design indicates that a 2000 MW(th) fusion reactor could produce as much at 364 x 10 6 scf/day of hydrogen which is equivalent in heating value to 20,000 barrels/day of gasoline. This would fuel about 500,000 autos based on average driving patterns. 7. A factor of three reduction in coal feed (tons/day) could be achieved for syngas production if hydrogen from a fusion-HTE system were used to gasify coal, as compared to a conventional syngas plant using coal-derived hydrogen

22 CFR Appendix B to Part 513 - Certification Regarding Debarment, Suspension, Ineligibility and Voluntary Exclusion-Lower Tier...

Science.gov (United States)

2010-04-01

..., Ineligibility and Voluntary Exclusion-Lower Tier Covered Transactions B Appendix B to Part 513 Foreign Relations... Debarment, Suspension, Ineligibility and Voluntary Exclusion—Lower Tier Covered Transactions Instructions... is providing the certification set out below. 2. The certification in this clause is a material...

Safety and deterministic failure analyses in high-beta D-D tokamak reactors

International Nuclear Information System (INIS)

Selcow, E.C.

1984-01-01