scholarly journals Criticality safety evaluation for the Advanced Test Reactor enhanced low enriched uranium fuel elements

2016 ◽  
Author(s):  
Leland M. Montierth
Keyword(s):  
Safety Evaluation ◽  
Uranium Fuel ◽  
Enriched Uranium ◽  
Test Reactor ◽  
Fuel Elements ◽  
Criticality Safety

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.

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

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.

Thermal Analysis of the FSP-1 Experiment in the Advanced Test Reactor

2016 ◽  
Author(s):  
Grant L. Hawkes ◽  
Nicolas E. Woolstenhulme
Keyword(s):  
Thermal Analysis ◽  
Flow Instability ◽  
National Laboratory ◽  
Safety Evaluation ◽  
Thermal Safety ◽  
Primary Coolant ◽  
Coolant Pump ◽  
Safety Margins ◽  
Enriched Uranium ◽  
Test Reactor

The U.S. High Performance Research Reactor Conversions fuel development team is focused on developing and qualifying the uranium-molybdenum (U-Mo) alloy monolithic fuel to support conversion of domestic research reactors to low enriched uranium. Several previous irradiations have demonstrated the favorable behavior of the monolithic fuel. The Full Scale Plate 1 (FSP-1) fuel plate experiment will be irradiated in the northeast (NE) flux trap of the Advanced Test Reactor (ATR). This fueled experiment contains six aluminum-clad fuel plates consisting of monolithic U-Mo fuel meat. Three different types of fuel plates with matching pairs for a total of six plates were analyzed. These three types of plates are: full burn, intermediate power, and thick meat. A thermal analysis has been performed on the FSP-1 experiment to be irradiated in the ATR at the Idaho National Laboratory (INL). A thermal safety evaluation was performed to demonstrate that the FSP-1 irradiation experiment complies with the thermal-hydraulic safety requirements of the ATR Safety Analysis Report (SAR). The ATR SAR requires that minimum safety margins to critical heat flux and flow instability be met in the case of a loss of commercial power with primary coolant pump coast-down to emergency flow. The thermal safety evaluation was performed at 26 MW NE lobe power to encompass the expected range of operating power during a standard cycle. Additional safety evaluations of reactivity insertion events, loss of coolant event, and free convection cooling in the reactor and in the canal are used to determine the response of the experiment to these events and conditions. This paper reports and shows that each safety evaluation complies with each safety requirement of the ATR SAR.

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