Engineering topics

Daniel, W. E.

Publications and source records attributed to Daniel, W. E..

6 records

DOE OSTI2023

Demonstration of the Blending of the H-Canyon 2nd U Cycle with Natural U to Produce a HALEU Solution

Continued growth in the demand for high assay low enriched uranium (HALEU) is projected to support the conversion of US high performance research reactors from high to low enrichment and the development and deployment of a new generation of advanced reactors. Current options to meet the growing US need for HALEU include (1) blend-down of excess of highly enriched uranium (HEU) from the nuclear weapons programs, (2) blend-down of HEU metal from other stockpiles, or (3) recycle of irradiated HEU recovered from spent nuclear fuel (SNF). The recycle of HEU from SNF has been performed at the Savannah River Site (SRS) H-Canyon facility for nearly two decades to produce 4.95 wt % U-235 for sale and subsequent use in fuel for Tennessee Valley Authority (TVA) reactors. The HALEU produced in H-Canyon will not exceed the U-236 concentration limit in the ASTM C1462 standard for U metal enriched to more than 15% and less than 20% U-235, which applies to advanced reactors.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2020

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

The H-Canyon facility is currently using the 6.1D dissolver for the dissolution of Material Test Reactor (MTR) fuel and the 6.4D dissolver for the dissolution of High Flux Isotope Reactor (HFIR) fuel using mercury-catalyzed HNO₃ dissolution flowsheets. The processing strategy for both dissolvers involves the dissolution of multiple charges of fuel per batch. After the designated heating cycle, the dissolvers are opened, and the charging wells are probed to determine if the MTR or HFIR fuel has dissolved. If undissolved fuel fragments are beyond a certain height, the dissolver must be closed and heated for an additional amount of time to dissolve the remaining material. In recent MTR fuel dissolutions, “high probes” (i.e., excessive undissolved material) were frequently observed, which resulted in extended dissolution times. The suspected cause of the high probes was the incomplete dissolution of the L-Bundle End Cap, rather than the fuel or fuel bundles. The End Cap is hypothesized to be binding in the insert well and not dropping into the acid as the L-Bundle and fuel dissolve. Once the End Cap is dislodged by the probe and drops into the acid, the dissolution rate of the End Cap appears to be significantly reduced compared to the dissolution rate of the fuel and other parts of the L-Bundle. A similar issue has also been observed with the lifting bail on the HFIR fuel carriers. During HFIR fuel dissolutions, the lifting bail on the outer carrier has resulted in high probes due to incomplete dissolution. In one case, a partially dissolved bail was caught in one of the insert well holes which prevented the probe from going to the bottom of the well.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2019

Dissolution Flowsheet for U-10Mo Scrap Generated from the Fabrication of High Performance Research Reactor Fuel

The Savannah River National Laboratory was requested to develop dissolution flowsheets for low enriched uranium scrap streams generated during the fabrication of high performance research reactor (HPRR)fuel. The scrap streams include U-10Mo-Zr foil and rejected Al-clad plates. Co-rolled U-10Mo-Zr foils and Alclad U-10Mo-Zr mini-plates which have been through the hot isostatic pressing process were obtained from BWX Technologies, Inc. for use in this work. Small-scale dissolution experiments were performed to identify the flowsheet conditions required to safely and efficiently dissolve the fuel fabrication scrap for subsequent U recovery. Experiments were performed to demonstrate the dissolution of the U-10Mo-Zr foil, removal of the Al cladding from the mini-plates, and the dissolution of the mini-plates following cladding removal.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2018

Demonstration of Chemical Decladding and Disposition Options for Non-Al Clad Fuels in H-Canyon

Aqueous disposition of non-Al clad fuels was studied in order to determine if H-Canyon would be a viable disposition option for this type of L-Basin fuel. A review of the L-Basin fuel types and its condition was done suggesting two major cladding types, Zircaloy and 304L stainless steel needed to be studied. Dissolution flowsheets options were reviewed. Sulfex and Zirflex processes were chosen as best for H-Canyon integration. Both process flowsheets were demonstrated on a lab scale to determine decladding rate, and off-gas and waste production. The resulting data suggested decladding in H-Canyon was an option but dissolver corrosion as well as off-gas and waste generation needed to be addressed. Small scale dissolution in a hot cell of smaller damaged fuel is a viable option with the flowsheets tested.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2018

Optimized Dissolution Flowsheet for Uranium Metal

The U.S. Department of Energy’s National Nuclear Security Administration (NNSA) has entered into cooperative agreements with commercial businesses to establish a reliable domestic source of 99 Mo that will be produced without the use of highly enriched uranium (HEU).

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2018

Dissolution of Material Test Reactor Fuel in an H-Canyon Dissolver

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 flow sheet, 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.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗