Department Of Energy Complex Research Articles

Caustic recycle from high-salt nuclear wastes using a ceramic-membrane salt-splitting process

Abstract An electrochemical salt-splitting process, based on sodium-ion selective ceramic membranes, is being developed to recover and recycle sodium hydroxide from high-salt radioactive tank wastes in the U.S. Department of Energy complex. The ceramic membranes are from a family of materials known as sodium (Na), super-ionic conductors (NaSICON). Two membrane compositions based on the rare-earth elements, neodymium and dysprosium, and a new proprietary material, NAS-D, have been fabricated as disks and are currently being tested with waste simulants. The membranes have been incorporated into a polyethylene scaffold for implementation into commercially available plate-and-frame electrochemical cells. A purified caustic product with a sodium hydroxide in excess of 3 M was produced from waste simulants with the Dy- and Nd-NaSICON membranes. This is the nominal concentration for onsite recycle and higher concentrations are expected. Membrane fouling was not observed, even though gibbsite {A1(OH) 3 } was precipitated in large amounts during some of the runs. Preliminary testing of the NAS-D material indicates that a sodium current density of 38 mA/cm 2 with a sodium current efficiency of approximately 90% is achievable over 1000 h of operation with an applied potential of 4.5 V.

U.S. Department of Energy Participation in the Development of Emergency Response Planning Guidelines: The Program and Process

Abstract An Emergency Response Planning Guidelines (ERPG) program has been established by the chemical industry and the American Industrial Hygiene Association, with the coordination of the Organization Resources Counselors, Inc. (ORC), to address the need for reliable, consistent, and well-documented emergency planning guidelines. The U.S. Department of Energy (DOE), through the ORC and established task forces and the American Industrial Hygiene Association, is participating by supporting development of ERPGs for chemicals used in DOE facilities. This article describes the DOE's process for prioritizing chemicals used within the DOE complex for development of basic information packages which provide suggested values in support of ERPG determination. This report also describes many of the guidelines developed for use in control of workplace exposure to toxic chemicals and why they are inappropriate for emergency response planning. The ERPG program is described, the reasons for its implementation are given...

A Regulator’s Perspective on Tritium Handling

Tritium handling will continue throughout the foreseeable future within the U.S. Department of Energy complex. Changes are occurring that emphasize greater care in tritium handling. Technological improvements (e.g. `hardware` advances) are only part of the solution. The other area of improvement concerns the support or `software` side. Improved programs and procedures affecting operations, maintenance, surveillance, and emergency response are being implemented. The heightened emphasis on worker safety issues is the discussion of the two major assessments and their lessons learned. 10 refs.