Accident Analyses for Conversion of the University of Missouri Research Reactor (MURR) from Highly-Enriched to Low-Enriched Uranium

Stillman, J. A.; Feldman, E.E.; Jalůvka, David; Wilson, E.; Foyto, L.; Kutikkad, K.; McKibben, J.C.; Peters, N. J.

doi:10.2172/1345227

Cited by 6 publications

(51 citation statements)

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“…This is in agreement with the Preliminary UMo Report [1]. No specific melting temperature was discussed in reports on analyses done for HFIR [3], MURR [4], or NBSR [5]. Analyses for MITR [6] utilized a melting temperature of 1135°C, closer to the melting point of pure uranium (1132°C).…”

Section: Melting Temperature Of U-10mo Monolithic Fuelsupporting

confidence: 75%

“…The Preliminary UMo Report [1] [20,21]. Analyses for the ATR [7] use 17.0 g/cm 3 , while those for NBSR [5] selected a density of 17.2 g/cm 3 , and MURR [4] and MITR [6] both use 17.02 g/cm 3 for the room temperature density of unirradiated U-10Mo. All of these values are within 1.2% of the value proposed in the Preliminary UMo report, an acceptable variation.…”

Section: Dependence Of U-mo Alloy Fuel Density On Molybdenum Contentmentioning

confidence: 99%

“…The assumptions for density used by the five USHPRRs to be converted (ATR, HFIR, MITR, MURR, and NBSR) are compared to the linear fit given by equation 2.1 and the recommended value from the Preliminary UMo Report [1] (17.13 g/cm 3 from Appendix C) in Figure 2.2. The density used for MITR [6] and MURR [4] ascribes approximately 1% porosity to the fuel analysis, which allows for the uncertainty given the lack of density data on prototypic foils. Confirmation of the density during prototypic fuel fabrication is required since there is a degree of uncertainty in the "fully-dense" or ideal density, and there may be some measureable level of porosity despite the nearly fully dense U-10Mo fuel foil that is expected after rolling the cast material.…”

Section: Dependence Of U-mo Alloy Fuel Density On Molybdenum Contentmentioning

confidence: 99%

“…However, because these fits are all based on a single set of measurements, it is strongly recommended, and considered imperative, to collect a set of density values on samples with comparable porosity to prototypic as-fabricated foils to establish the accurate values. Lastly, NBSR [24], MURR [4], and MITR [25] do not explicitly address the temperature-dependence of density in their safety analyses because they neglect the thermal expansion of the fuel. Therefore, to conserve mass, temperature dependence of the density is also neglected in the analyses.…”

Section: Comparison Of the Temperature Dependence Of Density To Prelimentioning

confidence: 99%

“…Since irradiation does not change the mass of the fuel, the fuel core dimensions and fuel density are typically modeled as constant throughout the fuel lifetime. It should be noted, however, that MITR [6], MURR [4], and NBSR [5] incorporate assumptions for the change of the thickness of the coolant channel gap as a function of burnup in the analyses models. The coolant channel gap reduction is assumed to include the effect of fuel swelling as well as fuel creep and oxide formation on the surface of the fuel plate.…”

Section: Comparison To the Correlations Used In Analyses For The Ushpmentioning

confidence: 99%

See 4 more Smart Citations

Review of the Technical Basis for Properties and Fuel Performance Data Used in HEU to LEU Conversion Analysis for U-10Mo Monolithic Alloy Fuel

Jamison

Stillman

Jalůvka

et al. 2020

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Section: Melting Temperature Of U-10mo Monolithic Fuelsupporting

confidence: 75%

Section: Dependence Of U-mo Alloy Fuel Density On Molybdenum Contentmentioning

confidence: 99%

Section: Dependence Of U-mo Alloy Fuel Density On Molybdenum Contentmentioning

confidence: 99%

Section: Comparison Of the Temperature Dependence Of Density To Prelimentioning

confidence: 99%

Section: Comparison To the Correlations Used In Analyses For The Ushpmentioning

confidence: 99%

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Review of the Technical Basis for Properties and Fuel Performance Data Used in HEU to LEU Conversion Analysis for U-10Mo Monolithic Alloy Fuel

Jamison

Stillman

Jalůvka

et al. 2020

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Evaluation of Thin Plate Hydrodynamic Stability through a Combined Numerical Modeling and Experimental Effort

Tentner

Bojanowski

Feldman

et al. 2017

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An experimental and computational effort was undertaken in order to evaluate the capability of the fluid-structure interaction (FSI) simulation tools to describe the deflection of a Missouri University Research Reactor (MURR) fuel element plate redesigned for conversion to lowenriched uranium (LEU) fuel due to hydrodynamic forces. Experiments involving both flat plates and curved plates were conducted in a water flow test loop located at the University of Missouri (MU), at conditions and geometries that can be related to the MURR LEU fuel element. A wider channel gap on one side of the test plate, and a narrower on the other represent the differences that could be encountered in a MURR element due to allowed fabrication variability. The difference in the channel gaps leads to a pressure differential across the plate, leading to plate deflection. The induced plate deflection the pressure difference induces in the plate was measured at specified locations using a laser measurement technique. High fidelity 3-D simulations of the experiments were performed at MU using the computational fluid dynamics code STAR-CCM+ coupled with the structural mechanics code ABAQUS. Independent simulations of the experiments were performed at Argonne National Laboratory (ANL) using the STAR-CCM+ code and its built-in structural mechanics solver. The simulation results obtained at MU and ANL were compared with the corresponding measured plate deflections. ANL/RTR/TM-16/9Evaluation of Thin Plate Hydrodynamic Stability through a Combined Numerical Modeling and Experimental Effort ii velocity as expected and the maximum deflection for multiple experiments performed with an average flow velocity near 4.3 m/s was found to range between 5.5-7.0 mil. Due to the apparatus the plate deflection could only be measured along an azimuthally-centered line. Therefore simulations of the curved-plate experiments were performed with two models: a model that assumes that the channels are azimuthally uniform and a model that assumes azimuthally varying channels. The results obtained with the azimuthally uniform model agree well with the measured results. The azimuthally uniform model predicts a deflection of 5.6 mil for the average coolant velocity of 4.25 m/s, which under-estimated by 8% the 6.06 mil fit of the measured deflections at this fluid velocity. The results obtained with the azimuthally varying model provide a measure of the sensitivity of the deflection results to the geometry of the curved plate. The azimuthally varying model over-estimates the measured plate deflection at the leading edge by approximately 80% for an average coolant velocity of 4.0 m/s. The measured values, even at their upper 95% confidence limit of the best fit, remain bounded by the azimuthally non-uniform model.Based on the modeling of experiments there are certain points to consider relative to the expected stability of a prototypic LEU MURR fuel plate. The comparison of FSI simulation results with the measured experimental plate deflections shows that when the plate and...

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Safety Analysis of the Mo-99 Production Upgrade to the University of Missouri Research Reactor (MURR) with Highly-Enriched and Low-Enriched Uranium Fuel

Stillman

Feldman

Pham

et al. 2019

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The University of Missouri (MU) has been working in conjunction with Argonne National Laboratory (ANL) in the National Nuclear Security Administration (NNSA) Material Management and Minimization (M3) Reactor Conversion Program to support conversion of the University of Missouri-Columbia Research Reactor (MURR®) from highly enriched uranium (HEU) to low-enriched uranium (LEU) fuel. MURR is one of five U.S. High Performance Research Reactors (USHPRR) plus a critical facility that plans to convert to the use of LEU fuel. ANL/RTR/TM-18/16 Safety Analysis of the Mo-99 Production Upgrade to the University of Missouri Research Reactor (MURR) with Highly Enriched and Low-Enriched Uranium Fuel ii ANL/RTR/TM-18/16 Safety Analysis of the Mo-99 Production Upgrade to the University of Missouri Research Reactor (MURR) with Highly Enriched and Low-Enriched Uranium Fuel iv installed. Thus, the upgrade causes a change in the location of the maximum HEU fuel temperature resulting from the limiting LOFA, which is consistent with the shift in the core power distribution that occurs due to the upgrade. For the LEU core, the minimum margin to the fuel temperature safety limit for the limiting LOFA with the 2017-RBM-99 upgrade is 232 °C and occurs in an EOL fuel plate. This is the same margin as was predicted for the limiting LOFA for the PSAR analysis. The location of the minimum margin moves from plate 23 of the fuel element in core position 8 in the PSAR analysis to plate 23 of the fuel element in core position 4 with the upgrade. With more margin than the other scenarios, all LOFA transient results are considered to have very adequate margins to the burnupdependent fuel temperature safety limit. Because there is no change to the HEU or LEU nominal fuel element loadings and an overall negligible effect on the fuel burnup as a result of the 2017-RBM-99 upgrade, the radiological consequences of the maximum hypothetical accident and fuel handling accident were not evaluated in this work. As found in the PSAR analysis, for any event where a release is considered in the current HEU SAR, the radiological consequences after conversion remain lower than the regulatory limits. In summary, the Mo-99 production upgrade to MURR with the 2017-RBM-99 device has been found to cause a shift in the core power distribution for both HEU and LEU cores relative to the PSAR analysis. The predicted steady-state margins to flow instability with the upgrade are adequate for both HEU and LEU cores. The margins with the upgrade are lower than those predicted in the PSAR analysis for both HEU and LEU, but the margin for LEU is larger than that for HEU. For postulated transient accidents, the upgrade causes a slight decrease in the minimum margin to a fuel temperature safety limit based on the fuel blister threshold temperature. There is a 9 °C reduction in the safety margin for HEU for the most limiting accident evaluated under conditions specified in NUREG-1537. For a reference LEU core, the minimum safety margin for the most limiting transient accident with ...

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Accident Analyses for Conversion of the University of Missouri Research Reactor (MURR) from Highly-Enriched to Low-Enriched Uranium

Cited by 6 publications

References 0 publications

Review of the Technical Basis for Properties and Fuel Performance Data Used in HEU to LEU Conversion Analysis for U-10Mo Monolithic Alloy Fuel

Review of the Technical Basis for Properties and Fuel Performance Data Used in HEU to LEU Conversion Analysis for U-10Mo Monolithic Alloy Fuel

Evaluation of Thin Plate Hydrodynamic Stability through a Combined Numerical Modeling and Experimental Effort

Safety Analysis of the Mo-99 Production Upgrade to the University of Missouri Research Reactor (MURR) with Highly-Enriched and Low-Enriched Uranium Fuel

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