scholarly journals CONTINUOUS ENERGY COMET SOLUTION TO A SMALL MODULAR ADVANCED HIGH-TEMPERATURE REACTOR BENCHMARK PROBLEM (SmAHTR)

2021 ◽  
Vol 247 ◽  
pp. 05002
Author(s):  
Farzad Rahnema ◽  
Dingkang Zhang
Keyword(s):  
Monte Carlo ◽  
High Temperature ◽  
National Laboratory ◽  
Benchmark Problems ◽  
High Fidelity ◽  
Oak Ridge ◽  
Continuous Energy ◽  
High Temperature Reactor ◽  
Relative Differences ◽  
High Computational Efficiency

The continuous energy coarse mesh transport (COMET) method is a hybrid stochasticdeterministic solver that provides transport solutions to heterogeneous reactor cores. In this paper, COMET is tested against continuous energy Monte Carlo in solving the recently developed stylized Small Modular Advanced High-Temperature Reactor (SmAHTR) Benchmark Problems based on the Oak Ridge National Laboratory pre-conceptual design (core configurations). These problems are well-suited to test the performance of advanced neutronics tools because of their unique neutronics characteristics such as the multiple heterogeneities. The COMET solutions for the three benchmark problems were found to agree very well with the continuous energy Monte Carlo reference solutions. The discrepancy in the core eigenvalue (k-eff) varied from 40 pcm to 51 pcm. The average and maximum relative differences in the pin fission densities were in the range of 0.20% to 0.21% and 0.77% to 0.94%, respectively. It was also found that COMET was more than 2,000 times fast than MCNP. It can be concluded that COMET can model the SmAHTR core configuration with high fidelity and significantly high computational efficiency.

scholarly journals Prediction calculations for the first criticality of the HTR-PM using the PANGU code

2021 ◽  
Vol 32 (9) ◽  
Author(s):  
Ding She ◽  
Bing Xia ◽  
Jiong Guo ◽  
Chun-Lin Wei ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Monte Carlo ◽  
High Temperature ◽  
Power Plant ◽  
Uncertainty Analysis ◽  
Nuclear Data ◽  
High Fidelity ◽  
Pebble Bed ◽  
Input Model ◽  
High Temperature Reactor ◽  
High Temperature Gas

AbstractThe high-temperature reactor pebble-bed module (HTR-PM) is a modular high-temperature gas-cooled reactor demonstration power plant. Its first criticality experiment is scheduled for the latter half of 2021. Before performing the first criticality experiment, a prediction calculation was performed using PANGU code. This paper presents the calculation details for predicting the HTR-PM first criticality using PANGU, including the input model and parameters, numerical results, and uncertainty analysis. The accuracy of the PANGU code was demonstrated by comparing it with the high-fidelity Monte Carlo solution, using the same input configurations. It should be noted that keff can be significantly affected by uncertainties in nuclear data and certain input parameters, making the criticality calculation challenge. Finally, the PANGU is used to predict the critical loading height of the HTR-PM first criticality under design conditions, which will be evaluated in the upcoming experiment later this year.

scholarly journals EVALUASI DAN PERKEMBANGAN PEMBUATAN BAHAN BAKAR KERNEL UO2 DI PTAPB-BATAN YOGYAKARTA

2007 ◽  
Vol 10 (1) ◽  
Author(s):  
Hidayati Hidayati ◽  
Sri Rinanti Susilowati ◽  
Didiek Herhady
Keyword(s):  
High Temperature ◽  
National Laboratory ◽  
Sol Gel ◽  
Oak Ridge ◽  
Oak Ridge National Laboratory ◽  
High Temperature Reactor

EVALUASI DAN PERKEMBANGAN PEMBUATAN BAHAN BAKAR KERNEL UO2 DI PTAPBBATANYOGYAKARTA Telah dilakukan evaluasi pembuatan bahan bakar kernel UO2 sertaperkembangannya di Bidang Kimia dan Teknologi Proses Bahan (BKTPB) – PTAPB - BATAN Yogyakarta.Pembuatan kernel UO2 telah dilakukan dengan metode gelasi internal maupun eksternal. Metode gelasiinternal dilakukan dengan cara kombinasi proses KEMA-HKFA (Keuringvan Electrotecnische Materialenat Arnhem-Hkernforchungsanlage) maupun dengan proses ORNL (Oak Ridge National Laboratory),sedangkan metode gelasi eksternal dilakukan dengan proses emulsifikasi NUKEM (Nuclear Chemie undMetalurgie Gmbh). Dengan metode gelasi internal, telah dilakukan berbagai optimasi kondisi prosesnya.Hasil sementara menunjukkan bahwa proses yang paling baik adalah proses ORNL menggunakan mediagelasi TCE (tricloro etilena). Dengan metode gelasi eksternal, telah diperoleh beberapa kondisi optimum,namun masih perlu dilakukan optimasi lebih lanjut. Untuk memilih metode gelasi internal atau eksternaltergantung pada kemudahan proses, murah secara ekonomi serta yang memberikan hasil terbaik.Pemilihan metode belum bisa diputuskan karena belum semua variabel proses dioptimasi. Penelitianmengenai pelapisan kernel UO2 menggunakan silikon karbida (SiC) maupun pirokarbon (PyC) barumerupakan tahap awal, sehingga masih diperlukan optimasi berbagai variabel prosesnya. Penelitianpembuatan kernel UO2 di BKTPB – BATAN Yogyakarta direncanakan untuk pembuatan inti elemen bakarbentuk bola untuk HTR (High Temperature Reactor) dan dikembangkan sebagai bahan awal prosespembuatan pelet (proses SGMP = Sol-Gel Microsphere Pelletization) untuk PHWR (Pressurized HeavyWater Reactor).

The Modelling and Coupling Methodology of ANSYS CFX Using Porous Media for PB-AHTR

2013 ◽  
Author(s):  
Linsen Li ◽  
Haomin Yuan ◽  
Kan Wang
Keyword(s):  
Porous Media ◽  
Monte Carlo ◽  
Steady State ◽  
High Temperature ◽  
Monte Carlo Code ◽  
First Principle ◽  
Pebble Bed ◽  
Coupled Calculation ◽  
Ansys Cfx ◽  
High Temperature Reactor

This paper introduces a first-principle steady-state coupling methodology using the Monte Carlo Code RMC and the CFD code CFX which can be used for the analysis of small and medium reactors. The RMC code is used for neutronics calculation while CFX is used for Thermal-Hydraulics (T-H) calculation. A Pebble Bed-Advanced High Temperature Reactor (PB-AHTR) core is modeled using this method. The porous media is used in the CFX model to simulate the pebble bed structure in PB-AHTR. This research concludes that the steady-state coupled calculation using RMC and CFX is feasible and can obtain stable results within a few iterations.

Fabrication of Grade 91 Materials Experience in Oil and Gas Applications

2020 ◽  
Author(s):  
Bhadresh A. Prajapati ◽  
Jorge A. Penso
Keyword(s):  
High Temperature ◽  
Success Factors ◽  
Thermal Stresses ◽  
National Laboratory ◽  
Welding Parameters ◽  
Steam Generation ◽  
Creep Ductility ◽  
Ethane Conversion ◽  
Oak Ridge ◽  
Grade 91

Abstract A modified 9-Cr alloy was developed by Oak Ridge National Laboratory, in early 1980s, to increase high temperature capabilities of ferritic steels for superheater tubing. The material improved high temperature creep properties by controlling alloying elements and microstructure. The material was added to ASME BPVC in 1983 (thru Code Case 1943) as Grade 91. Higher yield and tensile strength, in comparison to other low-Cr alloy steels (like Grade 22), allowed for fabrication of thinner component wall thickness. This in-turn reduced susceptibility to through-wall thermal stresses during transient events. Directionally this also reduced material costs. Consequently, petrochemical industries have utilized Grade 91 in applications at Heat Recovery Steam Generation units (HRSG), Steam Methane Reformers (SMR), CO2 Boilers and as convection coils in Ethane conversion units. Grade 91 material has complex microstructure and requires careful control of welding parameters to assure crack free welds that provide adequate creep ductility and retain creep strength at high temperatures. The current guidelines documented in API 582 and Technical Report 938 provide limited insights on success factors for weldability. Grade 91 material use has been growing in the recent past Petrochemicals Complex and in offshore applications, at once-throw steam generators (OTSG). The aim of this paper is to share experience on welding parameters. Guidance needs be adjusted to specific projects and repair activities.

Transient Modeling of Advanced High Temperature Reactor (AHTR) in RELAP5/SCDAPSIM/MOD 4.0

2018 ◽  
Author(s):  
Hsun-Chia Lin ◽  
Sheng Zhang ◽  
Shanbin Shi ◽  
Xiaodong Sun ◽  
Richard Christensen
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchangers ◽  
Ambient Air ◽  
Normal Operation ◽  
Forced Circulation ◽  
Oak Ridge ◽  
Decay Heat ◽  
High Temperature Reactor ◽  
Relap5 Code

The Advanced High Temperature Reactor (AHTR) is a fluoride-salt-cooled high-temperature reactor (FHR) design concept that is currently being developed at Oak Ridge National Laboratory for efficient production of electricity with improved safety features. Transient analyses of different scenarios are critical to demonstrate the safety of the AHTR design. An AHTR reactor model has been developed using RELAP5/SCDAPSIM/MOD 4.0. Thermodynamic and transport properties of three molten fluoride salts, namely FLiBe, FLiNaK, and KF-ZrF4, have been implemented into the RELAP5 code. The AHTR RELAP5 model consists of a reactor core, an upper plenum, a lower plenum, three primary loops, and three Direct Reactor Auxiliary Cooling Systems (DRACS) loops. DRACS Heat Exchangers (DHX) and Natural Draft Heat Exchangers (NDHX) are important components of DRACS and provide coupling between the primary loops and DRACS loops, and DRACS loops and air chimneys, respectively. Single-wall fluted tube heat exchanger designs have been proposed for the DHX and the NDHX to improve heat transfer performance in the two heat exchangers, and heat transfer correlations for fluted tubes have also been implemented into the RELAP5 code. In this study, steady-state reactor normal operation and two transient scenarios are analyzed with the RELAP5 AHTR model. Based on a thermal hydraulics Phenomena Identification Ranking Table (PIRT) exercise, loss of forced circulation (LOFC) and loss of multiple DRACS loops are selected as the two transients for analysis. During transients, the decay heat is removed by the ambient air, fully relying on natural circulation/convection. The results of both transient scenarios show sufficient decay heat removal capabilities of DRACS with the proposed design.

High Temperature Performance of Cast CF8C-Plus Austenitic Stainless Steel

2010 ◽  
Author(s):  
Philip J. Maziasz ◽  
Bruce A. Pint
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
High Temperature ◽  
Austenitic Stainless Steel ◽  
Gas Turbines ◽  
National Laboratory ◽  
Austenitic Stainless Steels ◽  
Medium Size ◽  
Temperature Oxidation ◽  
Oak Ridge

Covers and casings of small to medium size gas turbines, can be made from cast austenitic stainless steels, including grades such as CF8C, CF3M, or CF10M. Oak Ridge National Laboratory (ORNL) and Caterpillar have developed a new cast austenitic stainless steel, CF8C-Plus, that is a fully-austenitic stainless steel, based on additions of Mn and N to the standard Nb-stabilized CF8C steel grade. The Mn addition improves castability, as well as increasing the alloy solubility for N, and both Mn and N act synergistically to boost mechanical properties. CF8C-Plus steel has outstanding creep-resistance at 600°–900°C, which compares well with Ni-based superalloys like alloys X, 625, 617 and 230. CF8C-Plus also has very good fatigue and thermal fatigue resistance. It is used in the as-cast condition, with no additional heat-treatments. While commercial success for CF8C-Plus has been mainly for diesel exhaust components, this steel can also be considered for gas-turbine and microturbine casings. The purpose of this paper is to demonstrate some of the mechanical properties and update the long-term creep-rupture data, and to present new data on the high-temperature oxidation behavior of these materials, particularly in the presence of water vapor.

scholarly journals Experimental studies in high temperature aqueous chemistry at Oak Ridge National Laboratory

1997 ◽  
Vol 69 (5) ◽  
pp. 905-914 ◽  
Author(s):  
R. E. Mesmer ◽  
D. A. Palmer ◽  
J. M. Simonson ◽  
H. F. Holmes ◽  
P. C. Ho ◽  
...  
Keyword(s):  
High Temperature ◽  
National Laboratory ◽  
Experimental Studies ◽  
Aqueous Chemistry ◽  
Oak Ridge ◽  
Oak Ridge National Laboratory

Developing New Cast Austenitic Stainless Steels With Improved High-Temperature Creep Resistance

2007 ◽  
Author(s):  
Philip J. Maziasz ◽  
John P. Shingledecker ◽  
Neal D. Evans ◽  
Michael J. Pollard
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Creep Strength ◽  
Stainless Steels ◽  
Creep Resistance ◽  
National Laboratory ◽  
Austenitic Stainless Steels ◽  
Alloy Development ◽  
Oak Ridge ◽  
Wide Range

Oak Ridge National Laboratory (ORNL) and Caterpillar have recently developed a new cast austenitic stainless steel, CF8C-Plus, for a wide range of high-temperature applications, including diesel exhaust components and turbine casings. The creep-rupture life of the new CF8C-Plus is over ten times greater than that of the standard cast CF8C stainless steel, and the creep-strength is about double. Another variant, CF8C-Plus Cu/W has been developed with even more creep strength at 750–850°C. The creep-strength of these new cast austenitic stainless steels is close to that of Ni-based superalloys like 617. CF8C-Plus steel was developed in about 1.5 years using an “engineered microstructure” alloy development approach, which produces creep resistance based on formation of stable nano-carbides (NbC) and prevention of deleterious intermetallics (sigma, Laves). CF8C-Plus steel won a 2003 R&D 100 Award, and to date, over 32,000 lb have been produced in various commercial component trials. The current commercialization status of the alloy is summarized.

Sign in / Sign up

Export Citation Format

Share Document