Preliminary Design Analysis of Hot Gas Ducts for a Nuclear Hydrogen System of 200 MWt

2008 ◽  
Author(s):  
Kee-Nam Song ◽  
Yong-Wan Kim
Keyword(s):  
Chemical Process ◽  
High Energy ◽  
Design Analysis ◽  
Normal Operation ◽  
Primary Circuit ◽  
Preliminary Design ◽  
Constant Flow ◽  
Strength Evaluation ◽  
Hot Gas ◽  
Hydrogen System

Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source for a nuclear hydrogen generation. The VHTR can produce hydrogen from heat and water by using a thermo-chemical process or from heat, water, and natural gas by steam reformer technology. Korea Atomic Energy Research Institute (KAERI) is in the process of carrying out a nuclear hydrogen system by considering the indirect cycle gas cooled reactors that produce heat at temperatures in the order of 950°. The nuclear hydrogen system is planning to produce hydrogen by using nuclear energy and a thermo-chemical process. Helium gas is the choice for the coolant of the nuclear hydrogen system since it is an inert gas, with no affinity to a chemical or nuclear activity; therefore a radioactivity transport in the primary circuit of the nuclear hydrogen system is minimal under a normal operation. Moreover, its gaseous nature avoids problems related to a phase change and water-metal reactions and therefore improves its safety. A coaxial double-tube hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger (IHX) for the nuclear hydrogen system. In this study, a preliminary design analysis for the primary and secondary HGDs of the nuclear hydrogen system was carried out. These preliminary design activities include a preliminary decision on the geometric dimensions, a preliminary strength evaluation and an appropriate material selection. A preliminary decision on the geometric dimensions of the HGDs was undertaken based on three engineering concepts, such as a constant flow velocity model (CFV model), a constant flow rate model (CFR model), a constant hydraulic head model (CHH model), and also based on a heat balanced model (HB model). We compared the geometric dimensions and their preliminary strength evaluation results from the various models.

Preliminary Design Analysis of Hot Gas Ducts for the Nuclear Hydrogen System

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Kee-nam Song ◽  
Yong-wan Kim
Keyword(s):  
Material Selection ◽  
Design Analysis ◽  
Preliminary Design ◽  
Strength Evaluation ◽  
Hot Gas ◽  
Hydrogen System ◽  
Intermediate Heat Exchanger ◽  
Design Activities ◽  
Design Requirements ◽  
Reactor Pressure

Korea Atomic Energy Research Institute is in the process of carrying out a nuclear hydrogen system by considering the indirect cycle gas cooled reactors that produce heat at temperatures in the order of 950°C. A coaxial double-tube hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger for the nuclear hydrogen system. Recently, a preliminary design analysis for the primary and secondary hot gas ducts of the nuclear hydrogen system was carried out. These preliminary design activities include a preliminary decision on the geometric dimensions, a preliminary strength evaluation, and an appropriate material selection. In this study, a preliminary strength evaluation for the HGDs of the nuclear hydrogen system has been undertaken. Preliminary strength evaluation results for the HGDs showed that the geometric dimensions of the proposed HGDs would be acceptable for the design requirements.

Preliminary Design Analysis of a Hot Gas Ducts for the Nuclear Hydrogen System

2008 ◽  
Author(s):  
Kee-Nam Song ◽  
Yong-Wan Kim
Keyword(s):  
Material Selection ◽  
Design Analysis ◽  
Preliminary Design ◽  
Strength Evaluation ◽  
Hot Gas ◽  
Hydrogen System ◽  
Intermediate Heat Exchanger ◽  
Design Activities ◽  
Design Requirements ◽  
Reactor Pressure

Korea Atomic Energy Research Institute (KAERI) is in the process of carrying out a nuclear hydrogen system by considering the indirect cycle gas cooled reactors that produce heat at temperatures in the order of 950 °C. A coaxial double-tube hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger (IHX) for the nuclear hydrogen system. Recently, a preliminary design analysis for the primary and secondary hot gas ducts of the nuclear hydrogen system was carried out. These preliminary design activities include a preliminary decision on the geometric dimensions, a preliminary strength evaluation and an appropriate material selection. In this study, a preliminary strength evaluation for the HGDs of the nuclear hydrogen system has been undertaken. Preliminary strength evaluation results for the HGDs showed that the geometric dimensions of the proposed HGDs would be acceptable for the design requirements.

scholarly journals A Safety Re-Evaluation of the AVR Pebble Bed Reactor Operation and Its Consequences for Future HTR Concepts

2008 ◽  
Author(s):  
Rainer Moormann
Keyword(s):  
Fission Product ◽  
End Of Life ◽  
Fission Products ◽  
Normal Operation ◽  
Primary Circuit ◽  
Pebble Bed ◽  
Pebble Bed Reactor ◽  
Hot Gas ◽  
Design Basis ◽  
Gas Tight

The AVR pebble bed reactor (46 MWth) was operated 1967–1988 at coolant outlet temperatures up to 990°C. Also because of a lack of other experience the AVR operation is a basis for future HTRs. This paper deals with insufficiently published unresolved safety problems of AVR and of pebble bed HTRs. The AVR primary circuit is heavily contaminated with dust bound and mobile metallic fission products (Sr-90, Cs-137) which create problems in current dismantling. The evaluation of fission product deposition experiments indicates that the end of life contamination reached several percent of a single core inventory. A re-evaluation of the AVR contamination is performed in order to quantify consequences for future HTRs: The AVR contamination was mainly caused by inadmissible high core temperatures, and not — as presumed in the past — by inadequate fuel quality only. The high AVR core temperatures were detected not earlier than one year before final AVR shut-down, because a pebble bed core cannot be equipped with instruments. The maximum core temperatures were more than 200 K higher than precalculated. Further, azimuthal temperature differences at the active core margin were observed, as unpredictable hot gas currents with temperatures > 1100°C. Despite of remarkable effort these problems are not yet understood. Having the black box character of the AVR core in mind it remains uncertain whether convincing explanations can be found without major experimental R&D. After detection of the inadmissible core temperatures, the AVR hot gas temperatures were strongly reduced for safety reasons. Metallic fission products diffuse in fuel kernel, coatings and graphite and their break through takes place in long term normal operation, if fission product specific temperature limits are exceeded. This is an unresolved weak point of HTRs in contrast to other reactors and is particularly problematic in pebble bed systems with their large dust content. Another disadvantage, responsible for the pronounced AVR contamination, lies in the fact that activity released from fuel elements is distributed in HTRs all over the coolant circuit surfaces and on graphitic dust and accumulates there. Consequences of AVR experience on future reactors are discussed. As long as pebble bed intrinsic reasons for the high AVR temperatures cannot be excluded they have to be conservatively considered in operation and design basis accidents. For an HTR of 400 MWth, 900°C hot gas temperature, modern fuel and 32 fpy the contaminations are expected to approach at least the same order as in AVR end of life. This creates major problems in design basis accidents, for maintenance and dismantling. Application of German dose criteria on advanced pebble bed reactors leads to the conclusion that a pebble bed HTR needs a gas tight containment even if inadmissible high temperatures as observed in AVR are not considered. However, a gas tight containment does not diminish the consequences of the primary circuit contamination on maintenance and dismantling. Thus complementary measures are discussed. A reduction of demands on future reactors (hot gas temperatures, fuel burn-up) is one option; another one is an elaborate R&D program for solution of unresolved problems related to operation and design basis accidents. These problems are listed in the paper.

Preliminary Design Analysis of a Hot Gas Duct for the NHDD Program at Korea

2008 ◽  
Vol 33-37 ◽  
pp. 1227-1232
Author(s):  
Kee Nam Song ◽  
Hyeong Yeon Lee ◽  
Yong Wan Kim ◽  
Soo Bum Lee
Keyword(s):  
Material Selection ◽  
Preliminary Evaluation ◽  
Preliminary Design ◽  
Strength Evaluation ◽  
Design Concepts ◽  
Hot Gas ◽  
Creep Fatigue ◽  
Intermediate Heat Exchanger ◽  
Design Activities ◽  
Reactor Pressure

Korea Atomic Energy Research Institute (KAERI) is in the process of carrying out a Nuclear Hydrogen Development and Demonstration (NHDD) Program by considering the indirect cycle gas cooled reactors that produce heat at temperatures in the order of 950°C. A coaxial doubletube hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger (IHX) for the NHDD program. Recently, a preliminary design evaluation for the hot gas duct of the NHDD program was carried out. These preliminary design activities include a preliminary decision on the geometric dimensions, a preliminary strength evaluation, an appropriate material selection, and identifying the design code for the HGD. In this study, a preliminary strength evaluation for the HGD of the NHDD program has been undertaken based on the HTR-10 design concepts. Also, a preliminary evaluation of the creep-fatigue damage for a high temperature HGD structure has been carried out according to the draft code case for Alloy 617. Preliminary strength evaluation results for the HGD showed that the geometric dimensions of the proposed HGD would be acceptable for the design requirements.

Actual Design Space Methodology for Preliminary Design Analysis of Switched Reluctance Machines

2021 ◽  
Vol 57 (1) ◽  
pp. 397-408
Author(s):  
Roberto Rocca ◽  
Fabio Giulii Capponi ◽  
Giulio De Donato ◽  
Savvas Papadopoulos ◽  
Federico Caricchi ◽  
...  
Keyword(s):  
Design Space ◽  
Design Analysis ◽  
Preliminary Design ◽  
Switched Reluctance ◽  
Switched Reluctance Machines ◽  
Actual Design

scholarly journals Fault Detection Method Based on Global-Local Marginal Discriminant Preserving Projection for Chemical Process

Processes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 122
Author(s):  
Yang Li ◽  
Fangyuan Ma ◽  
Cheng Ji ◽  
Jingde Wang ◽  
Wei Sun
Keyword(s):  
Feature Extraction ◽  
Fault Detection ◽  
Chemical Process ◽  
Detection Method ◽  
Detection Performance ◽  
Detection Methods ◽  
Normal Operation ◽  
Discriminative Feature ◽  
Inherent Feature ◽  
Global And Local

Feature extraction plays a key role in fault detection methods. Most existing methods focus on comprehensive and accurate feature extraction of normal operation data to achieve better detection performance. However, discriminative features based on historical fault data are usually ignored. Aiming at this point, a global-local marginal discriminant preserving projection (GLMDPP) method is proposed for feature extraction. Considering its comprehensive consideration of global and local features, global-local preserving projection (GLPP) is used to extract the inherent feature of the data. Then, multiple marginal fisher analysis (MMFA) is introduced to extract the discriminative feature, which can better separate normal data from fault data. On the basis of fisher framework, GLPP and MMFA are integrated to extract inherent and discriminative features of the data simultaneously. Furthermore, fault detection methods based on GLMDPP are constructed and applied to the Tennessee Eastman (TE) process. Compared with the PCA and GLPP method, the effectiveness of the proposed method in fault detection is validated with the result of TE process.

scholarly journals Study on electrochemical principle and characteristic curve of nickel hydrogen battery for mine

2021 ◽  
Vol 233 ◽  
pp. 01071
Author(s):  
Gaojian Ren
Keyword(s):  
Characteristic Curve ◽  
High Capacity ◽  
High Energy ◽  
Cycle Life ◽  
Normal Operation ◽  
Long Cycle Life ◽  
Soc Estimation ◽  
Terminal Voltage ◽  
Intelligent Management ◽  
Mh Battery

As a kind of high-energy secondary battery, mining Ni MH battery is very suitable for mine backup power because of its advantages of high capacity, high power, no pollution, long cycle life, strong charging and discharging ability and high safety. This paper mainly introduces the electrochemical reaction of Ni MH battery under normal operation, overcharge and over discharge, introduces the types and components of Ni MH battery, describes the change curve of charging and discharging terminal voltage with time under different conditions, analyzes the self discharge situation of Ni MH battery under different conditions, and analyzes the cycle life and safety of Ni MH battery. The software and hardware design of battery intelligent management and SOC estimation analysis provide the basic basis.

Preliminary Design of a Beam Dump for the High-Energy Proton Accelerator of PEFP

2008 ◽  
Vol 52 (9(3)) ◽  
pp. 799-804
Author(s):  
Jiho Kim ◽  
Do Heon Kim ◽  
Wan Young Maeng ◽  
Choong-Sup Gil
Keyword(s):  
High Energy ◽  
Proton Accelerator ◽  
Preliminary Design ◽  
High Energy Proton ◽  
Beam Dump ◽  
Energy Proton

Numerical Approach for the Consideration of Hold Time Effects

2014 ◽  
Author(s):  
Sven H. Reese ◽  
Johannes Seichter ◽  
Dietmar Klucke ◽  
H. Ertugrul Karabaki ◽  
Wolfgang Mayinger
Keyword(s):  
Hold Time ◽  
Austenitic Steels ◽  
Normal Operation ◽  
Primary Circuit ◽  
Published Data ◽  
Fatigue Lifetime ◽  
Time Effects ◽  
Positive Effects ◽  
Surge Line ◽  
Circuit Components

In recent years the Environmentally Assisted Fatigue (EAF) became an item, which has to be considered additionally in terms of ensuring a conservative determination of the actual component’s health status resp. the CUF. For practical application, the consideration of the so called Fen-factor leads to the reduction of the admissible cycles in fatigue calculations. Beyond that the influence of elevated temperatures has been identified as one parameter having a negative influence on the admissible cycles as well. For example the German KTA 3201.2 defines for austenitic steels separate fatigue curves for temperatures above 80°C and for temperatures below 80°C. In summary on the one hand parameters influencing component’s lifetime negatively have to be considered in terms of conservative calculations. On the other hand, there are other parameters which influence the component’s fatigue lifetime in a positive manner. As such positive effects are neglected so far, CUF allowing for EAF tend to become over conservative leading to oversized components. Therefore, positive effects should be considered as well in the framework of a comprehensive and detailed analysis making sure not to overdesign components. When taking a closer look on the operational behavior of primary circuit components, fatigue loading is mainly defined by long steady-state periods with no significant changes in the loadings and by normally short outage periods with no thermal loading. For example fatigue of a PWR surge-line is mostly caused by short in-surge and out-surge events during start-up or shut-down of the plant. Normal operation transients mostly not cause fatigue relevant events in the surge-line. Fatigue of PWR spray-lines is primarily generated by very few spray-events during a one-year period of operation. Spray events are mainly caused by significant load ramps. Subsequently the fatigue status of primary circuit components is controlled by long periods with no fatigue relevant loading at operating temperature and few additional loading patterns in between. Experimental investigations have shown that hold time effects have a positive influence on fatigue lifetime of austenitic stainless steel materials. Anyhow, no quantification of these effects has been published in recent years. Within this publication an engineering based approach will be developed to quantify the hold time effect based on literature and published data. On the basis of a practical example the influence of hold time effects will be quantified and a direct comparison to lifetime reducing effect of EAF and temperature will be drawn.

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