The EFTTRA-T3 irradiation experiment on inert matrix fuels

Neeft, E.A.C.; Bakker, K.; Schram, R.P.C.; Conrad, R.; Konings, R.J.M.

doi:10.1016/s0022-3115(03)00176-4

Cited by 57 publications

(19 citation statements)

References 9 publications

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“…The calculated dissolution curves for MgO under this assumption are plotted as dashed lines in both Figure 16 and Figure 20(a). For the dissolution test conducted at 60 C with magnetic bar stirring in both HNO 3 and H 2 SO 4 , the experimental data follow the calculated curves, suggesting that the proposed model is a good estimate. While for the one conducted at 60 C in ultrasonic bath, the last measured data point falls below the calculated curve, which is probably due to inefficient agitation causing a diffusion barrier to form and slow down the process.…”

Section: Dissolution Behavior Of Mgo-nd 2 Zr 2 O 7 Compositessupporting

confidence: 57%

“…The ultrasonic power was recorded from three individual tests and averaged to be 10.3 W/s. As discussed before, however, the dissolution rate of MgO was not increased by ultrasound compared with static dissolution, and Nd 2 Zr 2 O 7 didn't dissolve in HNO 3 . The inefficiency of ultrasonic dissolution of MgO is probably due to the size of the composite and its porous structure developed during dissolution.…”

Section: Effects Of Agitation Methods and Dissolution Temperature On Dmentioning

confidence: 67%

“…1,2 Magnesium oxide (MgO) is a promising candidate for inert matrix (IM) materials due to its high melting point (2827 °C) 2 , high thermal conductivity (13 W/K·m at 1000 °C) 2 , good neutronic properties, and irradiation stability 3,4 However, MgO reacts with water and hydrates easily, which prevents it from being used in light water reactors (LWRs) as an IM. To improve the hydration resistance of MgO-based inert matrix materials, Medvedev 5 and coworkers have recently investigated the introduction of a secondary phase that acts as a hydration barrier.…”

Section: Introductionmentioning

confidence: 99%

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Neri Final Technical Report, De-Fc07-O5id14647, Optimization of Oxide Compounds for Advanced Inert Matrix Materials

Nino¹

2009

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The following is a technical report summarizing all the procedures, experiments, simulations and technical findings of this NERI project. For additional information, details or technical questions regarding this project, please contact jnino@mse.ufl.edu MgO and NDZ......................................................................69 8.4. Grain Size Dependence of MgO and NDZ Polycrystal Thermal Conductivity75 8.5 2009 Composite Processing and Characterization IntroductionIn order to reduce the current excesses of plutonium (both weapon grade and reactor grade) and other transuranium elements, a concept of inert matrix fuel (IMF) has been proposed for an uranium free transmutation of fissile actinides which excludes continuous uranium-plutonium conversion in thermal reactors and advanced systems. 1,2 Magnesium oxide (MgO) is a promising candidate for inert matrix (IM) materials due to its high melting point (2827 °C) 2 , high thermal conductivity (13 W/K·m at 1000 °C) 2 , good neutronic properties, and irradiation stability 3,4 However, MgO reacts with water and hydrates easily, which prevents it from being used in light water reactors (LWRs) as an IM. To improve the hydration resistance of MgO-based inert matrix materials, Medvedev 5 and coworkers have recently investigated the introduction of a secondary phase that acts as a hydration barrier. An MgO-ZrO 2 composite was specifically studied and the results showed that the composite exhibited improved hydration resistance than pure MgO. However, ZrO 2 is insoluble in most acids except HF, which is undesirable for fuel reprocessing. Moreover, the thermal conductivity of ZrO 2 is low and typically less than 3 W·m at 1000 °C. 6 In search for an alternative composite strategy, Nd 2 Zr 2 O 7 , an oxide compound with pyrochlore structure, has been proposed recently as a corrosion resistant phase, and MgO-Nd 2 Zr 2 O 7 composites have been investigated as potential IM materials. at 1000 °C for the MgO-Nd 2 Zr 2 O 7 composite with 90 vol% MgO was recently calculated and reported. 8,9 Other simulations proposed that the MgO-pyrochlore composites could exhibit higher radiation stability than previously reported. 10 Final optimization of the composite microstructure was performed on the 70 vol% MgONd 2 Zr 2 O 7 composite that burnup calculations had shown to have the closest profile to that of MOX fuel. Theoretical calculations also indicated that a homogeneous 70 vol% MgO composite could achieve the desired microstructure that would result in satisfying the dual requirements of good thermal properties. Experimental Procedures Composite Synthesis Solid State Synthesis of Nd 2 Zr 2 O 7Stoichiometric ratios of Nd 2 O 3 (Alfa Aesar 99.9%) and ZrO 2 (99.7%) were added to spherical 3 mm and 10 mm yttria stabilized zirconia (YSZ) milling media in a PTFE (polytetrafluoroethylene) ball mill jar with 100 ml of deionized water and 3 ml of ammonium polyacrylate dispersant (20 vol% Darvan 821A in deionized water). The slurry was milled for 24 hours on the ball mill at 85 rpm ...

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Section: Dissolution Behavior Of Mgo-nd 2 Zr 2 O 7 Compositessupporting

confidence: 57%

Section: Effects Of Agitation Methods and Dissolution Temperature On Dmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 99%

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Neri Final Technical Report, De-Fc07-O5id14647, Optimization of Oxide Compounds for Advanced Inert Matrix Materials

Nino¹

2009

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“…While initially favored as a leading candidate and pursued in many research programs, irradiation experiments show that Spinel is likely not a suitable matrix candidate, as it shows large swelling, pellet fracturing, and high fission gas release [Neeft et al, 2003 andMeyer, 2006]. While fission gas release into the inner part of the fuel assembly is not a concern given that the fuel assemblies are vented, it does contribute to fuel swelling due to poor diffusion of the fission gases through the Spinel matrix.…”

Section: Selection Of An Appropriate Inert Matrix Fuelmentioning

confidence: 99%

“…A recent irradiation experiment on inert matrix fuels was conducted in order to compare the irradiation performance among several IMF options, and MgO was shown to be one of the top performers [Neeft et al, 2003]. With the MgO inert matrix, the Pu and MA could be either in the form of simple binary oxides or hosted in a zirconia-based phase, e.g.…”

Section: Selection Of An Appropriate Inert Matrix Fuelmentioning

confidence: 99%

Optimized Core Design of a Supercritical Carbon Dioxide-Cooled Fast Reactor

2008

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Spurred by the renewed interest in nuclear power, Gas-cooled Fast Reactors (GFRs) have received increasing attention in the past decade. Motivated by the goals of the Generation-IV International Forum (GIF), a GFR cooled by supercritical carbon dioxide (S-CO 2 ), fueled with Light Water Reactor spent fuel transuranics, and directly coupled with a Brayton cycle is under investigation as part of a larger research effort at MIT. While the original GFR chosen by the GIF is a 600MWh version using Helium as a coolant, the work presented here is for a 2400 MWd, core using S-CO 2 as a coolant, which has comparable thermal efficiency (-45%) at much lower temperatures (650"C v. 850 0 C) A reactor core for use in this direct cycle S-CO 2 GFR has been designed which satisfies established neutronic and thermal-hydraulic steady state design criteria, while concurrently supporting the Gen-IV criteria of sustainability, safety, proliferation, and economics. Use of innovative Tube-in-Duct (TID) fuel has been central to accomplishing this objective, as it provides a higher fuel volume fraction and lower fuel temperatures and pressure drop when compared to traditional pin-type fuel. Further, this large fuel volume fraction allows for a large enough heavy metal loading for a sustainable core lifetime without the need for external blankets, enhancing the proliferation resistance of such an approach.Use of Beryllium Oxide (BeO) as a diluent is explored as a means for both power shaping and coolant void reactivity (CVR) reduction in fast reactors. Results show that relatively flat power profiles can be maintained throughout a batch-loaded "battery" core life using a combination of enrichment and diluent zoning, due to the slight moderating effect of the BeO. Combining BeO diluent with the innovative strategy of using a thick volume of S-CO 2 coolant as the radial reflector yields negative CVR values throughout core life, a rare, if not unique accomplishment for fast reactors. The ability to maintain negative CVR comes from a combination of the effects of spectral softening due to the BeO diluent and the enhanced leakage upon voiding of the S-CO 2 radial reflector.In support of assessing the neutronic self-controllability of this core, a simple first-order steady state design metric is developed, modified from other established methodology to suit the uniqueness of this core concept. The results of this analysis show that the core will passively shut itself down without violation of established core thermal limits in the event of several limiting Anticipated Transients Without SCRAM (ATWS) scenarios, except for a Loss of Coolant Without SCRAM at End of Core life. Since most of the requisites for passive core shutdown have been demonstrated within the parameter uncertainties of current estimates, the candidate core design is deemed sufficiently safe. Further, design solutions for fixing this deficiency are proposed.Alternative cores using traditional pin-type fuel and innovative Internally-Cooled Annular Fuel (ICAF) have also be...

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