scholarly journals Accident Analysis for the NIST Research Reactor Before and After Fuel Conversion

2012 ◽  
Author(s):  
Baek J. ◽  
Diamond D. ◽  
A. Cuadra ◽  
A.L. Hanson ◽  
L-Y. Cheng ◽  
...  
Keyword(s):  
Research Reactor ◽  
Accident Analysis ◽  
Fuel Conversion ◽  
Before And After

Analysis of Reactivity Insertion Accidents for the NIST Research Reactor before and after Fuel Conversion

2014 ◽  
Vol 185 (1) ◽  
pp. 1-20 ◽  
Author(s):  
J. S. Baek ◽  
A. Cuadra ◽  
L.-Y. Cheng ◽  
A. L. Hanson ◽  
N. R. Brown ◽  
...  
Keyword(s):  
Research Reactor ◽  
Fuel Conversion ◽  
Before And After ◽  
Reactivity Insertion

scholarly journals RELAP5 SIMULATION FOR SEVERE ACCIDENT ANALYSIS OF RSG-GAS REACTOR

2018 ◽  
Vol 20 (1) ◽  
pp. 23 ◽  
Author(s):  
Andi Sofrany Ekariansyah ◽  
Endiah Puji Hastuti ◽  
Sudarmono Sudarmono
Keyword(s):  
Fuel Element ◽  
Secondary Flow ◽  
Research Reactor ◽  
Natural Circulation ◽  
Safety Analysis ◽  
Reactor Power ◽  
Severe Accident ◽  
Accident Analysis ◽  
Plate Temperature ◽  
The One

The research reactor in the world is to be known safer than power reactor due to its simpler design related to the core and operational chararacteristics. Nevertheless, potential hazards of research reactor to the public and the environment can not be ignored due to several special features. Therefore the level of safety must be clearly demonstrated in the safety analysis report (SAR) using safety analysis, which is performed with various approaches and methods supported by computational tools. The purpose of this research is to simulate several accidents in the Indonesia RSG-GAS reactor, which may lead to the fuel damage, to complement the severe accident analysis results that already described in the SAR. The simulation were performed using the thermal hydraulic code of RELAP5/SCDAP/Mod3.4 which has the capability to model the plate-type of RSG-GAS fuel elements. Three events were simulated, which are loss of primary and secondary flow without reactor trip, blockage of core subchannels without reactor trip during full power, and loss of primary and secondary flow followed by reactor trip and blockage of core subchannel. The first event will harm the fuel plate cladding as showed by its melting temperature of 590 °C. The blockage of one or more subchannels in the one fuel element results in different consequences to the fuel plates, in which at least two blocked subchannels will damage one fuel plate, even more the blockage of one fuel element. The combination of loss of primary and secondary flow followed by reactor trip and blockage of one fuel element has provided an increase of fuel plate temperature below its melting point meaning that the established natural circulation and the relative low reactor power is sufficient to cool the fuel element.Keywords: loss of flow, blockage, fuel plate, RSG-GAS, RELAP5 SIMULASI RELAP5 UNTUK ANALISIS KECELAKAAN PARAH PADA REAKTOR RSG-GAS. Reaktor riset di dunia diketahui lebih aman dari pada reaktor daya karena desainnya yang lebih sederhana pada teras dan karakteristika operasinya. Namun demikian, potensi bahaya reaktor riset terhadap publik dan lingkungan tidak bisa diabaikan karena beberapa fitur tertentu. Oleh karena itu, level keselamatan reaktor riset harus jelas ditunjukkan dalam Laporan Analisis Keselamatan (LAK) dalam bentuk analisis keselamatan yang dilakukan dengan berbagai macam pendekatan dan metode dan didukung dengan alat komputasi. Tujuan penelitian ini adalah untuk mensimulasikan beberapa kecelakaan parah pada reaktor RSG-GAS yang dapat menyebabkan kerusakan bahan bakar untuk memperkuat hasil analisis kecelakaan parah yang sudah ada dalam LAK. Simulation dilakukan dengan program perhitungan RELAP5/SCDAP/Mod3.4 yang memiliki kemampuan untuk memodelkan elemen bahan bakar tipe pelat di RSG-GAS. Tiga kejadian telah disimulasikan yaitu hilangnya aliran primer dan sekunder dengan kegagalan reaktor untuk dipadamkan, tersumbatnya beberapa kanal pendingin bahan bakar pada daya penuh, dan hilangnya aliran primer dan sekunder yang diikuti dengan tersumbatnya beberapa kanal pendingin bahan bakar setelah reaktor padam. Kejadian pertama akan membahayakan pelat bahan bakar dengan naiknya temperatur kelongsong hingga titik lelehnya yaitu 590 °C. Tersumbatnya satu atau beberapa kanal pada satu elemen bahan bakar menyebabkan konsekuensi yang berbeda pada pelat bahan bakar, dimana paling sedikit tersumbatnya 2 kanal akan merusak satu pelat bahan bakar, apalagi tersumbatnya satu elemen bahan bakar. Kombinasi antara hilangnya aliran pendingin primer dan sekunder yang diikuti dengan tersumbatnya satu kanal bahan bakar setelah reaktor dipadamkan menyebabkan naiknya temperatur kelongsong di bawah titik lelehnya yang berarti sirkulasi alam yang terbentuk dan daya yang terus turun cukup untuk mendinginkan elemen bahan bakar.Kata kunci: kehilangan aliran, penyumbatan, pelat bahan bakar, RSG-GAS, RELAP5

scholarly journals Measuring the Safety Effect of Raised Bicycle Crossings Using a New Research Methodology

1998 ◽  
Vol 1636 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Per Gårder ◽  
Lars Leden ◽  
Urho Pulkkinen
Keyword(s):  
Bayesian Approach ◽  
Research Methodology ◽  
Accident Analysis ◽  
Traffic Calming ◽  
Expert Model ◽  
Before And After ◽  
Study Methodology ◽  
Safety Effect ◽  
New Research ◽  
Before And After Study

Before-and-after study methodology was developed and applied to evaluating the effect on bicyclists’ safety of raising urban bicycle crossings by 4 to 12 cm. In total, 44 junctions were reconstructed in this way in Gothenburg, Sweden. Four of these were studied in detail. Before the implementations, bicyclists were riding either in the roadway or on separate paths parallel to the roadway. The paths then ended with short ramps or curb cuts at each cross street, and bicyclists used nonelevated, marked bicycle crossings, similar to pedestrian crosswalks but delineated by white painted rectangles rather than zebra stripes. The results show that the paths with raised crossings attracted more than 50 percent more bicyclists and that the safety per bicyclist was improved by approximately 20 percent due to the increase in bicycle flow, and with an additional 10 to 50 percent due to the improved layout. However, the increased bicyclist volume means that the total number of bicycle accidents is expected to increase. Besides accident analysis, the change in risk was estimated using four different methods: surveys of bicyclists and experts, respectively; conflict data; and a quantitative expert model. Using a Bayesian approach for combining the results shows that the most likely effect of raising the bicycle crossing is a risk reduction of around 30 percent, compared with the before situation with a conventional bicycle crossing. Motorists and pedestrians also saw safety benefits from this traffic-calming measure.

Advanced Fe-Cr Alloys Studied by Pulsed Low Energy Positron System Before and After Helium Ions Implantation

2009 ◽  
Author(s):  
Stanislav Sojak ◽  
Vladimi´r Krsˇjak ◽  
Werner Egger
Keyword(s):  
Research Reactor ◽  
Chromium Content ◽  
Depth Profiling ◽  
Positron Annihilation Spectroscopy ◽  
Implantation Dose ◽  
Low Energy ◽  
Microstructural Damage ◽  
Helium Ion ◽  
Before And After ◽  
Non Destructive

Positron annihilation spectroscopy (PAS) is a non-destructive technique which provides information about microstructural damage of structural materials. In this paper, the Pulsed Low Energy Positron System (PLEPS) at the research reactor FRM-II at TU Munich was used to study depth profiling of binary Fe-Cr alloys. Fe-Cr model alloys with different chromium content were investigated in the as-received state as well as after helium ion implantation (dose up to 6.24×1017 ions/cm−2). Measured results show changes in the size of defects after implantation and also in non-implanted specimens depending on the Cr content.

The Simulation of Decontamination Works in Premises of the Research Reactor in NRC “Kurchatov Institute”

2013 ◽  
Author(s):  
Alexey Danilovich ◽  
Oleg Ivanov ◽  
Victor Potapov ◽  
Sergey Smirnov ◽  
Vyacheslav Stepanov
Keyword(s):  
Remote Sensing ◽  
Research Reactor ◽  
Research Centre ◽  
Kurchatov Institute ◽  
Radiation Fields ◽  
Before And After ◽  
Reduce Radiation Dose ◽  
Spectrometric System ◽  
Remote Sensing Methods ◽  
Russian Research

Application of remote sensing methods using a spectrometric collimated system allows obtaining information about features of a formation of radiation fields in contaminated premises. This information helps in a preparation of a phased plan for dismantling of contaminated equipment. When the survey of technological premises of the research reactor at the Russian Research Centre “Kurchatov institute” was conducted the remote controlled collimated spectrometric system was used [1]. With its help the scanning of surveyed premises were carried out. As a result of this work, the distribution pattern of radionuclides activity was restored. The simulation of decontamination works was carried out and maps of the distribution of activity and dose rate for surveyed premises were plotted and superimposed on its photo for situations before and after decontamination. The use of obtained results will allow significantly reduce radiation dose for staff at work on dismantling.

Analysis of Loss-of-Flow Accidents for the NIST Research Reactor with Fuel Conversion from HEU to LEU

2015 ◽  
Vol 189 (1) ◽  
pp. 71-86 ◽  
Author(s):  
J. S. Baek ◽  
A. Cuadra ◽  
L.-Y. Cheng ◽  
A. L. Hanson ◽  
N. R. Brown ◽  
...  
Keyword(s):  
Research Reactor ◽  
Fuel Conversion

scholarly journals Startup, transition core, and molybdenum-99 production upgrade analyses for low-enriched uranium fuel conversion at the University of Missouri research reactor

2020 ◽  
Author(s):  
◽  
Wilson Cowherd
Keyword(s):  
Low Power ◽  
Research Reactor ◽  
The United States ◽  
Fuel Conversion ◽  
Reactor Physics ◽  
University Of Missouri ◽  
Safety Margins ◽  
Enriched Uranium ◽  
The University ◽  
The Impact

Under the direction of the United States Department of Energy (DOE) National Nuclear Security Administration (NNSA) Office of Material Management and Minimization (M3) Reactor Conversion Program, the University of Missouri Research Reactor (MURR®) plans to convert from highly enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. Low power physics startup test predictions, transition core planning, and analysis for a proposed fission-based molybdenum-99 production upgrade were done in support of LEU fuel conversion. As a first step to LEU fuel conversion, low-power physics tests will be performed to calculate reactor physics parameters. These parameters include flux distributions, coefficients of reactivity, and critical assembly measurements. To facilitate this test, reactor physics calculations were performed using MCNP5 to predict the values of these parameters. Implications of these predictions and areas of uncertainty in the prediction analysis are also discussed. Once MURR completes the testing of the initial LEU core, MURR will enter into a series of transition cycles until steady-state mixed-burnup operation is reached. A Python program was developed that incorporated the constraints of MURR operation while minimizing the time MURR will have to operate atypically during the transition cycles. The impacts of the transition cycles on experiment performance are reported, as well as the number of fuel elements needed. Finally, preliminary analysis on a proposed molybdenum-99 production device at MURR was performed. This analysis shows the impact on the reactor power distribution with implications to predicted safety margins as a part of the larger scope of the experiment analysis.

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