Reactor-Vessel Design Considering Radiation Effects

1964 ◽  
Vol 86 (4) ◽  
pp. 743-748 ◽  
Author(s):  
L. Porse
Keyword(s):  
Radiation Effects ◽  
Reactor Vessel ◽  
Closed Cycle ◽  
Irradiation Effects ◽  
Safe Operation ◽  
Plant Operator ◽  
Start Up ◽  
Fast Neutron Irradiation ◽  
Vessel Material ◽  
Metal Properties

Nuclear-vessel design involves consideration of changes in metal properties resulting from fast-neutron irradiation effects. This paper outlines precautions and design steps which can cope with these effects and insure safe operation of PWR closed-cycle-type reactor vessels for their planned life expectancy. Illustrations show workable stress levels as a function of temperature for the reactor-vessel material in nonirradiated and irradiated condition. A plot of equivalent pressure temperature relationships is shown as a guide for the plant operator during plant start-up and shutdown periods.

An Investigation of Fast Neutron Irradiation Effects on the Structure of Cu50Ti50 Metallic Glass

1988 ◽  
pp. 317-322
Author(s):  
Guoan Wu ◽  
Yuanda Dong ◽  
Keqin Xiao ◽  
Yizhen He ◽  
Longshu Wang ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Fast Neutron ◽  
Neutron Irradiation ◽  
Irradiation Effects ◽  
Fast Neutron Irradiation

HTGR Closed Cycle GT Plant Analysis: Options and Procedures for Startup With Hot Gas Injection

2002 ◽  
Author(s):  
K. N. Pradeep Kumar ◽  
A. Tourlidakis ◽  
P. Pilidis
Keyword(s):  
Power Plant ◽  
Heat Source ◽  
Nuclear Reactor ◽  
Gas Injection ◽  
Plant Analysis ◽  
Closed Cycle ◽  
Hot Gas ◽  
Mechanical Constraints ◽  
Start Up ◽  
Gas Turbine Power Plant

The Starting up and Shutting down of a closed cycle gas turbine power plant needs special attention due to the inter-dependable nature of the components. Achieving self-sustainability in a fast and efficient way within the mechanical constraints is the challenge in the start-up of a closed cycle. The Nuclear reactor as the heat source will add more complexity to the system. The paper looks into the various options available for the start up and shutdown of a closed cycle Helium turbine using a gas cooled reactor as the heat source. A comparative analysis of these options is carried out by simulating various operating scenarios using a Transient Simulation Computer Programme especially prepared for an HTGR Project called PBMR (Pebble Bed Modular Reactor), which is being carried out in South Africa. The simulation was focused on the power conversion side of the plant, which includes all the Turbocompressors, Turbogenerator, Heat exchangers, Valves etc. Based on the analysis and its findings, an outline of a start up and shutdown procedure for a 3-shaft Closed Cycle Turbine Power Plant using hot gas injection is proposed in the paper.

An Update on the Investigation of Fracture Toughness Properties of the High Flux Reactor Vessel From Surveillance Test Campaign in 2017

2019 ◽  
Author(s):  
M. Kolluri ◽  
F. H. E. de Haan – de Wilde ◽  
H. S. Nolles ◽  
A. J. M. de Jong
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Fracture Surface ◽  
Neutron Fluence ◽  
Reactor Vessel ◽  
Surveillance Program ◽  
High Flux ◽  
High Flux Reactor ◽  
Flux Reactor ◽  
Vessel Material

Abstract The reactor vessel of the High Flux Reactor (HFR) in Petten has been fabricated from Al 5154-O alloy grade with a maximum Mg content of 3.5 wt. %. The vessel experiences large amount of neutron fluences (notably at hot spot), of the order of 1027 n/m2, during its operational life. Substantial damage to the material’s microstructure and mechanical properties can occur at these high fluence conditions. To this end, a dedicated surveillance program: SURP (SURveillance Program) is executed to understand, predict and measure the influence of neutron radiation damage on the mechanical properties of the vessel material. In the SURP program, test specimens fabricated from representative HFR vessel material are continuously irradiated in two specially designed experimental rigs. A number of surveillance specimens are periodically extracted and tested to evaluate the changes in fracture toughness properties of the vessel as function neutron fluence. The surveillance testing results of test campaigns performed until 2015 were published previously in [1, 2]. The current paper presents fracture toughness and SEM results from the recent surveillance campaign performed in 2017. The fracture toughness specimen tested in this campaign received a thermal neutron fluence of 13.56 x1026 n/m2, which is ∼8.9 × 1025 n/m2 more than the thermal fluence received by the specimen tested in SURP 2015 campaign. These results from this campaign have shown no change in the fracture toughness from the values measured in the previous SURP campaign. The SEM observations are performed to study the fracture surface, to measure (by WDS) the transmutation Si formed near crack tip and to investigate various inclusions in the microstructure. SEM fracture surface investigation revealed a tortuous (bumpy) fracture surface constituting micro-scale dimples over majority of the fracture area. Islands of cleavage facets and secondary cracks have been observed as well. EDS analysis of various inclusions in the microstructure revealed presence of Fe rich inclusions and Mg-Si rich precipitates. Additionally, inclusions rich in Al-Mg-Cr-Ti were identified. Finally, changes in mechanical properties of Al 5154-O alloy with an increase in neutron fluence (or transmutation Si) are discussed in correlation with SEM microstructure and fracture morphology observed in SEM. TEM investigation of precipitate microstructure is ongoing and those results will be published in future.

scholarly journals New Start-up Method for a Closed-Cycle Compression System with Gas Bearings and Its Characteristics

2020 ◽  
Vol 33 (1) ◽  
Author(s):  
Huaqi Lian ◽  
Hong Wu ◽  
Yulong Li ◽  
Chengjun Rong
Keyword(s):  
Rotational Speed ◽  
Load Capacity ◽  
Initial Pressure ◽  
Frictional Resistance ◽  
Closed Cycle ◽  
High Rotational Speed ◽  
Compression System ◽  
Gas Bearings ◽  
Start Up ◽  
Working Medium

AbstractGas bearings, which have the advantages of low frictional resistance and power loss, high rotational speed and high temperature operation, and long life, are more suitable than are traditional liquid lubricated bearings because of their high precision, high rotational speed, and special condition support. However, the problem of starting a closed-cycle compression system with gas bearings still needs to be solved for practical application. Thus, a new start-up method for a closed-cycle compression system with aerostatic gas bearings is proposed in this paper. Further, this paper presents a numerical simulation and experimental investigation of the method’s feasibility and characteristics during the start-up process when the gas tank’s initial pressure is fixed. The results show that the gas tank volume is approximately directly proportional to the start-up time allowable, and a gas tank volume sufficiently small, which not only ensures the feasibility of start-up, but also affects other components only slightly, can be obtained. A perfect combination of radial and axial loads also can be achieved to make the start-up time allowable as long as possible. R134a is a better choice for the working medium than is air, as the start-up time allowable is longer, which leads to a smaller gas tank. This research proposes a new start-up method for a closed-cycle compression system with aerostatic gas bearings which has sufficient load capacity to support system during the start-up method.

Damped Absorber Optimization and Stability for Semi-Definite Systems Exhibiting Unstable Self-Excitation During Start-Up

1992 ◽  
Vol 114 (1) ◽  
pp. 47-53 ◽  
Author(s):  
J. R. Shadley ◽  
J. R. Sorem
Keyword(s):  
Computer Simulation ◽  
System Dynamics ◽  
Laboratory Testing ◽  
Submersible Pump ◽  
Safe Operation ◽  
Pump System ◽  
Electric Induction ◽  
First Case ◽  
Start Up ◽  
Electric Submersible Pump

Stability is examined with respect to the torque in the elastic element between motor and load in semi-definite systems exhibiting unstable self-excitation during start-up. Equations are provided for optimizing a motor-mounted damped absorber to minimize the torque fluctuations in the shafting between motor and load in semi-definite systems. Minimum damper inertia needed to stabilize the system is computed assuming optimum damping. Stability and damper optimization equations are applied to two cases involving unstable self-excitation in electric submersible pump systems. In the first case, unstable growth of torque amplitude in shafting between an electric induction motor and an inertial load was observed during start-up in laboratory testing. A computer simulation of the system dynamics demonstrated that the torque could be stabilized by adding a damped absorber to the motor. In a computer simulation for the second case, unstable torque fluctuations in the shafting of an electric submersible pump system were dramatically reduced by the addition of a damped absorber; however, stability was not achieved until the damper inertia was sufficiently increased. Stability is not always required for safe operation of electric submersible pumps. A computational model of the system dynamics during startup should be used to determine when stability is required.

Fast neutron irradiation effects—I. Dosimetry

1985 ◽  
Vol 26 (2) ◽  
pp. 211-220 ◽  
Author(s):  
Y Katsumura ◽  
Y Tabata ◽  
T Seguchi ◽  
N Hayakawa ◽  
K Yoshida ◽  
...  
Keyword(s):  
Fast Neutron ◽  
Neutron Irradiation ◽  
Irradiation Effects ◽  
Fast Neutron Irradiation

Acoustic Barkhausen Effect Observed in Various Steels

2017 ◽  
Vol 885 ◽  
pp. 208-215
Author(s):  
Gabor Por ◽  
Balazs Fekete ◽  
Peter Trampus
Keyword(s):  
Acoustic Emission ◽  
Source Localization ◽  
Fatigue Testing ◽  
Stress Test ◽  
Reactor Vessel ◽  
Acoustic Response ◽  
Barkhausen Effect ◽  
Acoustic Emission Sensors ◽  
Vessel Material

Carrying out fatigue testing of reactor vessel material 15H2MFA acoustic emission sensors were applied to follow changes. It is shown, that observed bursts can be explained only with appearance of acoustic Barkhausen Effect (ABE). Interesting source localization is shown during heat treatment and consecutive stress test, which can be explained acoustic emission due to material transition from martenzit phase to bainite phase. Observed ABE opens the way to apply it in industry using magnetic stresses to provoke acoustic response for characterization of the state of the magnetic materials.

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