Dissolution Flowsheet for High Flux Isotope Reactor Fuel

Mickalonis

2020

Section: Dissolution Rates Of L-bundle End Cap and Hfir Fuel Outer Casupporting

confidence: 90%

Section: Figure 3-13 Experiments 97 -Calculated Al-1100 Coupon Dissolmentioning

confidence: 99%

Section: Objectivementioning

confidence: 99%

Section: Comparison Of the End Cap Sidewall With The Dissolution Of Omentioning

confidence: 99%

“…The End Cap sidewall (coupon EC-E) had the lowest particle count (<100) with the lowest total particle area (225 μm 2 ). An area/particle ratio was also calculated based on these values.…”

Section: Metallurgical Analyses Of L-bundle End Cap and Hfir Fuel Outmentioning

confidence: 99%

See 3 more Smart Citations

Evaluation of the Dissolution Behavior of L-Bundle End Caps and HFIR Fuel Carriers

Mickalonis

2020

Dissolution of Material and Test reactor Fuel in an H-Canyon Dissolver

O'Rourke

2017

Self Cite

In an amended record of decision for the management of spent nuclear fuel (SNF) at the Savannah River Site, the US Department of Energy has authorized the dissolution and recovery of U from 1000 bundles of Al-clad SNF. The SNF is fuel from domestic and foreign research reactors and is typically referred to as Material Test Reactor (MTR) fuel. Bundles of MTR fuel containing assemblies fabricated from U-Al alloys (or other U compounds) are currently dissolved using a Hg-catalyzed HNO 3 flowsheet. Since the development of the existing flowsheet, improved experimental methods have been developed to more accurately characterize the offgas composition and generation rate during laboratory dissolutions. Recently, these new techniques were successfully used to develop a flowsheet for the dissolution of High Flux Isotope Reactor (HFIR) fuel. Using the data from the HFIR dissolution flowsheet development and necessary laboratory experiments, the Savannah River National Laboratory (SRNL) was requested to define flowsheet conditions for the dissolution of MTR fuels. With improved offgas characterization techniques, SRNL will be able define the number of bundles of fuel which can be charged to an H-Canyon dissolver with much less conservatism.Laboratory-scale experiments were performed to evaluate the dissolution of MTR fuels using both Al 1100 and 30 wt % U-Al alloys. The Al 1100 alloy was considered a representative surrogate since it provided an upper bound on the generation of flammable (i.e., H 2 ) gas during the dissolution process. The dissolution of the 30 wt % U-Al alloy proceeded at a slower rate than the Al 1100 alloy and was used to verify that the target Al concentration in solution could be achieved for the selected Hg concentrations. Raman spectroscopy was used to provide continuous monitoring of the concentration of H 2 and other permanent gases in the dissolution offgas allowing the development of H 2 generation rate profiles. The H 2 generation rates were subsequently used to evaluate how many L-Bundles could be dissolved in an H-Canyon dissolver without exceeding 60% of the calculated lower flammability limit (LFL) for H 2 at a given Hg concentration.Complete dissolution of the Al 1100 and 30 wt % U-Al alloys up to a final Al concentration of 2 M was obtained using a HNO 3 solution containing a 0.002 M Hg catalyst. However, following the dissolutions, solids were observed in the solutions. Analysis of the solids generally showed amorphous material or Si and SiO 2 which likely originated from the Si present in the alloys. No crystalline materials, such as UO 2 (NO 3 ) 2 or Al(NO3)3 were observed. Amorphous and silicon-containing solids from the dissolution of MTR fuels should be easily removed by the Head End centrifuge using the standard gelatin strike process. In experiments performed to develop the HFIR fuel dissolution flowsheet, the H 2 generation data showed that delaying the addition of Hg once the HNO 3 solution reached the boiling point can reduce the total offgas and H 2 generation rates. The delay...

Analysis of maximum allowable fragment heights during dissolution of high flux isotope reactor fuel in an h-canyon dissolver

2017

As part of the Spent Nuclear Fuel (SNF) processing campaign, H-Canyon is planning to begin dissolving High Flux Isotope Reactor (HFIR) fuel in late FY17 or early FY18. Each HFIR fuel core contains inner and outer fuel elements which were fabricated from uranium oxide (U 3 O 8 ) dispersed in a continuous Al phase using traditional powder metallurgy techniques. Fuels fabricated in this manner, like other SNF's processed in H-Canyon, dissolve by the same general mechanisms with similar gas generation rates and the production of H 2 . The HFIR fuel cores will be dissolved using a flowsheet developed by the Savannah River National Laboratory (SRNL) in either the 6.4D or 6.1D dissolver using a unique insert. Multiple cores will be charged to the same dissolver solution maximizing the concentration of dissolved Al. The recovered U will be down-blended into low-enriched U for subsequent use as commercial reactor fuel.