Neutron-physical and heat-engineering aspects of uranium-graphite reactors loaded with enriched-uranium fuel elements

Atomic Energy ◽  
2006 ◽  
Vol 101 (2) ◽  
pp. 606-610
Author(s):  
Yu. A. Artel’nyi ◽  
P. M. Gavrilov ◽  
A. A. Tsyganov
Keyword(s):  
Heat Engineering ◽  
Uranium Fuel ◽  
Enriched Uranium ◽  
Fuel Elements

Effects of Thickness of Zirconium Liner on Stress-Strain Characteristics of U10Mo Monolithic Plates

2013 ◽  
Author(s):  
Hakan Ozaltun ◽  
Robert M. Allen ◽  
You Sung Han
Keyword(s):  
Diffusion Barrier ◽  
Reactor Core ◽  
Stress Strain ◽  
Strain Behavior ◽  
Uranium Fuel ◽  
Plate Design ◽  
Enriched Uranium ◽  
Test Reactor ◽  
Irradiation Performance ◽  
Fuel Elements

The effects of the thickness of Zirconium liner on stress-strain behavior of monolithic fuel mini-plates during fabrication and irradiation processes were studied. Monolithic plate-type fuel elements is a new fuel form being developed for research and test reactors to achieve higher uranium densities which allows the use of low-enriched uranium fuel in reactor core. These fuel elements are comprised of a high density, low enrichment, U–Mo alloy based fuel foil encapsulated in a cladding material made of Aluminum. Early RERTR experiments indicated that the presence of an interaction layer between the fuel and cladding materials causes mechanical problems. To minimize the fuel/cladding interaction, employing a diffusion barrier between the cladding and the fuel materials was proposed. Current monolithic plate design employs a 0.025 mm thick, 99.8% pure annealed Zirconium diffusion barrier between the fuel foil (U10Mo) and the cladding materials (AL6061-O). To benchmark the irradiation performance, a number of plates were irradiated in the Advanced Test Reactor (ATR) with promising irradiation performance. To understand the effects of the thickness of the Zirconium diffusion barrier on the stress-strain behavior of the plates during fabrication, irradiation and shutdown stages, a representative plate from RERTR-12 experiments (Plate L1P7A0) was selected and simulated. Both fabrication and irradiation stages were considered. Simulations were repeated for various Zirconium thicknesses to understand the effects of the thickness of the diffusion barrier. Results of fabrication simulations indicated that Zirconium thickness has noticeable effects on foil’s stresses. Irradiation simulations revealed that the fabrication stresses of the foil would be relieved rapidly in the reactor. Results also showed that Zirconium thickness has little or no effects on irradiation and shutdown stresses.

scholarly journals Effects of the Foil Flatness on the Stress-Strain Characteristics of U10Mo Alloy Based Monolithic Mini-Plates

2014 ◽  
Author(s):  
Hakan Ozaltun ◽  
Pavel Medvedev
Keyword(s):  
Mechanical Performance ◽  
Peak Stress ◽  
Stress Strain ◽  
Strain Behavior ◽  
Uranium Fuel ◽  
Considerable Impact ◽  
Enriched Uranium ◽  
Fuel Elements ◽  
Cladding Material ◽  
Plate Type

The effects of the foil flatness on stress-strain behavior of monolithic fuel mini-plates during fabrication and irradiation were studied. Monolithic plate-type fuels are a new fuel form being developed for research and test reactors to achieve higher uranium densities. This concept facilitates the use of low-enriched uranium fuel in the reactor. These fuel elements are comprised of a high density, low enrichment, U–Mo alloy based fuel foil encapsulated in a cladding material made of Aluminum. To evaluate the effects of the foil flatness on the stress-strain behavior of the plates during fabrication, irradiation and shutdown stages, a representative plate from RERTR-12 experiments (Plate L1P756) was considered. Both fabrication and irradiation processes of the plate were simulated by using actual irradiation parameters. The simulations were repeated for various foil curvatures to observe the effects of the foil flatness on the peak stress and strain magnitudes of the fuel elements. Results of fabrication simulations revealed that the flatness of the foil does not have a considerable impact on the post fabrication stress-strain fields. Furthermore, the irradiation simulations indicated that any post-fabrication stresses in the foil would be relieved relatively fast in the reactor. While, the perfectly flat foil provided the slightly better mechanical performance, overall difference between the flat-foil case and curved-foil case was not significant. Even though the peak stresses are less affected, the foil curvature has several implications on the strain magnitudes in the cladding. It was observed that with an increasing foil curvature, there is a slight increase in the cladding strains.

scholarly journals Changes of the Neutron Flux of the Nuclear Reactor Triga Mark III Since the Conversion from High to Low 235U Enrichment

2021 ◽  
Vol 8 (2) ◽  
pp. 149-153
Author(s):  
C. Vázquez-López ◽  
O. Del Ángel-Gómez ◽  
R. Raya-Arredondo ◽  
S. S. Cruz-Galindo ◽  
J. I. Golzarri-Moreno ◽  
...  
Keyword(s):  
Neutron Flux ◽  
Nuclear Reactor ◽  
Research Reactor ◽  
Nuclear Research ◽  
Reactor Power ◽  
Uranium Fuel ◽  
Acrylic Sheet ◽  
Enriched Uranium ◽  
Reactor Operating ◽  
Fuel Elements

The neutron flux of the Triga Mark III research reactor was studied using nuclear track detectors. The facility of the National Institute for Nuclear Research (ININ), operates with a new core load of 85 LEU 30/20 (Low Enriched Uranium) fuel elements. The reactor provides a neutron flux around 2 × 1012 n cm-2s-1 at the irradiation channel. In this channel, CR-39 (allyl diglycol policarbonate) Landauer® detectors were exposed to neutrons; the detectors were covered with a 3 mm acrylic sheet for (n, p) reaction. Results show a linear response between the reactor power in the range 0.1 - 7 kW, and the average nuclear track density with data reproducibility and relatively low uncertainty (±5%). The method is a simple technique, fast and reliable procedure to monitor the research reactor operating power levels.

scholarly journals Transport of high enriched uranium fresh fuel from Yugoslavia to the Russian federation

2002 ◽  
Vol 17 (1-2) ◽  
pp. 71-76 ◽  
Author(s):  
Milan Pesic ◽  
Obrad Sotic ◽  
William Hopwood
Keyword(s):  
Russian Federation ◽  
Nuclear Weapons ◽  
Nuclear Material ◽  
Uranium Fuel ◽  
The Russian Federation ◽  
Enriched Uranium ◽  
Fuel Elements

This paper presents the relevant data related to the recent shipment (August 2002) of fresh highly enriched uranium fuel elements from Yugoslavia back to the Russian Federation for uranium down blending. In this way, Yugoslavia gave its contribution to the Reduced Enrichment for Research and Test Reactors (RERTR) Program and to the world's joint efforts to prevent possible terrorist actions against nuclear material potentially usable for the production of nuclear weapons.

scholarly journals Study of Neutronic and Temperature Distribution During Enrichment Reduction for BN-350 Reactor

2018 ◽  
Vol 26 (8) ◽  
pp. 151-156
Author(s):  
Jamal Mohammed Rashid Abda
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Transient Response ◽  
Coolant Flow ◽  
Uranium Fuel ◽  
Flow Loss ◽  
High Enrichment ◽  
Enriched Uranium ◽  
Fuel Elements

      This paper represents the neutronic and thermal-hydraulic calculations for the conversion of BN-350 from 27% to 7% enriched Uranium fuel elements. Mixed enrichment cores have been studied where low enrichment uranium (LEU) cores fresh fuel elements substitute gradually the high enrichment uranium (HEU) depleted fuel elements in the equilibrium core.     Thermal-hydraulic calculations have been carried out to determine changes in the characteristics of the converted reactor during steady-state conditions and transient response to a coolant flow loss.   

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