scholarly journals JSI TRIGA neutron and gamma field characterization by TLD measurements

2020 ◽  
Vol 225 ◽  
pp. 04034
Author(s):  
Klemen Ambrožič ◽  
Klaudia Malik ◽  
Barkara Obryk ◽  
Luka Snoj
Keyword(s):  
Radiation Field ◽  
Radiation Effects ◽  
Nuclear Reactor ◽  
Measurement Techniques ◽  
Field Measurements ◽  
Reactor Irradiation ◽  
Fission Chamber ◽  
Start Up ◽  
Gamma Field ◽  
Irradiation Facilities

A well characterized radiation field inside a research nuclear reactor irradiation facilities enables precise qualification of radiation effects to the irradiated samples such as nuclear heating or changes in their electrical or material properties. To support the increased utilization of the JSI TRIGA reactor irradiation facilities in the past few years mainly on account of testing novel detector designs, electronic components and material samples, we are working on increasing the neutron and gamma field characterization accuracy using various modeling and measurement techniques. In this paper we present the dose field measurements using thermo-luminescent detectors (TLD’s) with different sensitivities neutron and gamma sensitivities, along with multiple ionization and fission chamber. Experiment was performed in several steps from reactor start-up, steady operation and a rapid shutdown, during which the ionization and fission chamber signals were acquires continuously, while the TLD’s were being irradiated at different stages during reactor operation and after shutdown, to also capture response to delayed neutron and gamma field. The results presented in this paper serve for validation of JSI designed JSIR2S code for delayed radiation field determination, initial results of its application on the JSI TRIGA TLD measurements will also be presented.

Neutron Radiation Effects on Lubricants and O-Rings for Target and Accelerator Applications

2021 ◽  
Vol 1024 ◽  
pp. 127-133
Author(s):  
Matteo Ferrari ◽  
Aldo Zenoni ◽  
Yong Joong Lee ◽  
Alberto Andrighetto
Keyword(s):  
Gamma Radiation ◽  
Radiation Damage ◽  
Radiation Effects ◽  
Nuclear Reactor ◽  
Neutron Radiation ◽  
Radioactive Isotopes ◽  
Structural Level ◽  
Radiation Resistant ◽  
Under Construction ◽  
Neutron Radiation Effects

Lubricants and O-rings are necessarily used for the construction of many accelerator-driven facilities as spallation sources or facilities for the production of radioactive isotopes. During operation, such component will absorb high doses of mixed neutron and gamma radiation, that can degrade their mechanical and structural properties. Experimental radiation damage tests of these components are mandatory for the construction of the facility. Methodologies for irradiation in nuclear reactor mixed fields and post-irradiation examination of lubricating oils, greases and O-rings were developed and are here presented. Samples were characterized with standard mechanical and physical-chemical tests. Parametric studies on the dose rate effects have been performed on O-rings. A case studies for a specific O-ring application in a gate valve has been developed. Some of the tested samples showed a dramatic change of their properties with dose, while others remain stable. Results were collected on nine commercial greases, on one oil and on four commercial elastomeric O-rings. The most radiation resistant among the selected products are now considered for application in facilities under construction. The main mechanisms of neutron and gamma radiation damage on these polymers were investigated at the mechanical and structural level.

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.

Inverse Conduction Technique in Hankel Domain Using Infrared Thermography: Application to Droplet Stream Quenching a Metal Disk

2010 ◽  
Author(s):  
Franck Lelong ◽  
Michel Gradeck ◽  
Benjamin Re´my ◽  
Aboubacar Ouattara ◽  
Denis Maillet
Keyword(s):  
Infrared Thermography ◽  
Nuclear Reactor ◽  
Quantitative Estimation ◽  
Measurement Techniques ◽  
Non Invasive ◽  
Loss Of Coolant Accident ◽  
Key Points ◽  
Order Of Magnitude ◽  
Metal Disk ◽  
Droplet Stream

Cooling of a hot metal by a spray occurs in various situations. Such is the case for a loss of coolant accident in a nuclear reactor, where a generated spray impacts the fuel rod assemblies. Design of an experimental characterization setup for cooling a hot (600°C) disk shape Nickel sample by a stream of monodisperse droplets is presented here. Non-invasive excitation/measurement techniques have been used in order to implement an inverse technique for quantitative estimation of both wall heat flux and temperature: heating is made by induction and infrared thermography is used for rear face temperature measurement. Control and calibration of the losses are key points here: their level is of the same order of magnitude as the flux removed by the droplets. Examples of inversion are presented.

scholarly journals Thermal and epithermal neutron fluence rates in the irradiation facilities of the TRIGA IPR-R1 nuclear reactor

2010 ◽  
Vol 40 (1) ◽  
pp. 47-51 ◽  
Author(s):  
Dante Marco Zangirolami ◽  
Arno Heeren de Oliveira ◽  
Andréa Vidal Ferreira
Keyword(s):  
Nuclear Reactor ◽  
Epithermal Neutron ◽  
Neutron Fluence ◽  
Irradiation Facilities

scholarly journals Nondestructive Testing of Ceramic Hip Joint Implants with Laser Spot Thermography

2017 ◽  
Vol 62 (4) ◽  
pp. 2133-2139
Author(s):  
J. Roemer ◽  
L. Pieczonka ◽  
M. Juszczyk ◽  
T. Uhl
Keyword(s):  
Damage Detection ◽  
Measurement Techniques ◽  
Infrared Camera ◽  
Field Measurements ◽  
Ceramic Materials ◽  
Test Sample ◽  
Theoretical Background ◽  
Laser Spot ◽  
Signal Acquisition ◽  
Full Field

AbstractThe paper presents an application of laser spot thermography for damage detection in ceramic samples with surface breaking cracks. The measurement technique is an active thermographic approach based on an external heat delivery to a test sample, by means of a laser pulse, and signal acquisition by an infrared camera. Damage detection is based on the analysis of surface temperature distribution near the exciting laser spot. The technique is nondestructive, non-contact and allows for full-field measurements. Surface breaking cracks are a very common type of damage in ceramic materials that are introduced in the manufacturing process or during the service period. This paper briefly discusses theoretical background of laser spot thermography, describes the experimental test rig and signal processing methods involved. Damage detection results obtained with laser spot thermography are compared with reference measurements obtained with vibrothermography. This is a different modality of active thermography, that has been previously proven effective for this type of damage. We demonstrate that both measurement techniques can be effectively used for damage detection and quality control applications of ceramic materials.

Development of Ultrasonic Temperature Sensors for Ultra-High Temperature Measurement in Nuclear Reactor Vessel

2002 ◽  
Author(s):  
Kil-Mo Koo ◽  
Kwang-Soon Ha ◽  
Rae-Joon Park ◽  
Sang-Baik Kim ◽  
Hee-Dong Kim ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Measurement ◽  
Optimization Design ◽  
Nuclear Reactor ◽  
Initial Conditions ◽  
Measurement Techniques ◽  
Gap Formation ◽  
Melt Temperature ◽  
Infrared Thermometry ◽  
High Temperature Measurement

The temperature measurement of a very high temperature core melt is of importance in LAVA (lower-plenum Arrested Vessel Attack) experiment in which gap formation between core melt and the reactor lower head, and the effect of the gap on thermal behavior are to be measured. The existing temperature measurement techniques have some problems, where the thermocouple, one of the contact methods, is restricted to under 2000°C, and the infrared thermometry, one of the non-contact methods, is unable to measure an internal temperature and very sensitive to the interference from reacted gases. So, in order to solve these problems, the delay time of ultrasonic wavelets due to high temperature is suggested. One of the key initial conditions to be measured in LAVA is the initial corium melt temperature. To measure it, the LAVA measurement group has developed several kinds of UTS’s. As a first stage, a molten material temperature was measured up to 2314°C. Also, the optimization design of the UTS (ultrasonic temperature sensor) with persistence at the high temperature was suggested in this paper. And the utilization of the theory suggested in this paper and the efficiency of the developed system are certified by performing experiments.

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