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DOE OSTI2015

Saltstone Studies Using the Scaled Continuous Processing Facility

The Savannah River National Laboratory (SRNL) has supported the Saltstone Facility since its conception with bench-scale laboratory experiments, mid-scale testing at vendor facilities, and consultations and testing at the Saltstone Facility. There have been minimal opportunities for the measurement of rheological properties of the grout slurry at the Saltstone Production Facility (SPF); thus, the Scaled Continuous Processing Facility (SCPF), constructed to provide processing data related to mixing, transfer, and other operations conducted in the SPF, is the most representative process data for determining the expected rheological properties in the SPF. These results can be used to verify the laboratory scale experiments that support the SPF using conventional mixing processes that appropriately represent the shear imparted to the slurry in the SPF.

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DOE OSTI2015

Extending the lifetime of mixer paddles used in the production of a low-level radioactive cementitious waste form - 15624

The salt-stone Production Facility (SPF) at the Savannah River Site (SRS) immobilizes low-level radioactive salt solution as a cementitious waste form known as salt-stone. The mixer used in the SPF is a '10-inch' Readco-Kurimoto continuous mixer with paddles fabricated from a high toughness steel. salt-stone is processed daily at a rate of 9.46 E-03 m{sup 3}/s (150 gallons per minute) in a caustic and radioactive environment. The paddles have degraded much quicker than expected which limits production rates and increases outage times. Due to the high cost of the mixer and the limited maintenance due to the radioactive environment, a combination of material properties and paddle configuration must be employed to extend the lifetime of the paddles. This paper will discuss two wear tests conducted by the Savannah River National Laboratory (SRNL) to determine the optimum paddle configuration to reduce wear on the mixer paddles. The first wear test used the mixer design operated up to December 2011 as the baseline and the second test used the mixer design installed after December 2011 as its baseline. As a result of these tests, the SPF will be implementing a new paddle configuration in the mixer currently installed in the SPF process room. (authors)

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NASA NTRS1992

Rugged Noncontact Backshorts For Waveguides

Improved adjustable noncontact backshort for waveguide easily scaled to any frequency from 1 to 1,000 GHz, not vulnerable to wear, oxidation, or corrosion of contacts, and stronger and easier to fabricate. Will allow development of waveguide mixer and oscillator circuits at frequencies approaching 1,000 GHz, for atmospheric and astrophysical remote-sensing programs.

Mcgrath, William R.↗

DOE OSTI2024

Saltstone Paddles and Augers Materials of Construction Study

The Saltstone Production Facility (SPF) uses a 10-inch READCO continuous, co-rotating twin-screw mixer to mix the dry premix with the low-level radioactive waste (LLW) salt solution to produce fresh saltstone grout. The paddles and augers within the mixer degrade via erosion in the region where the salt solution is introduced into the mixer. After the paddles/augers erode to a point where the throughput impacts operations, the mixer is disassembled, the effected paddles/augers are replaced, and the mixer is reassembled. Saltstone Engineering indicated that this effort requires an approximately three-week outage. The objective of this task is to assess alternative materials of construction (MOCs) that will provide better erosion characteristics and decrease the frequency in which the paddles and augers need replacement. Previous Astralloy V studies looked only at Charpy Impact and Rockwell Hardness Testing. Each of these will be examined for different alloys as well as Miller Testing (abrasion to determine wear) which will provide a good assessment of an alloy’s erosion/wear characteristics. The following facts concerning the current and proposed alloys for Saltstone Paddles and Augers are provided in this report. • Current Astralloy V material and alloy E52100 had the most favorable Miller Testing Results. • Charpy Impact Testing did not correlate with Miller Testing Results. • Hardness Testing correlated with Miller Testing results meaning that higher hardness will provide more favorable wear resistance. • Further investigation of E52100 and various tool grade steels is recommended for achieving wear resistant properties.

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