Donald E. Mueller is a senior research and development staff member in the Radiation Transport and Criticality (RTC) Group in the Nuclear Science and Technology Division. He received B.S. and M.S. degrees in nuclear engineering from the University of Illinois in 1983 and 1984, respectively. Mr. Mueller’s M.S. thesis research involved analysis background considerations for an alpha particle diagnostic system proposed for the Tokamak Fusion Test Reactor. He also served in the United States Marine Corps from 1975 to 1979, attaining the rank of Sergeant (E-5), separating with an Honorable Discharge. Prior to joining ORNL, he worked for Westinghouse Electric Corporation where his responsibilities included pressurized-water reactor (PWR) reload design and safety analyses; nuclear criticality safety (NCS) of handling, shipping, and storage of PWR and boiling-water reactor fresh and spent fuel; and the design, implementation, testing, and troubleshooting of reactor, reactor instrumentation, control rod drive logic cabinets, and position indication, radioactive material transport, and radiation detection models in PWR nuclear power plant training simulators. Mr. Mueller is a coauthor on three patents related to the storage of PWR fuel. He joined ORNL in 1992, where his responsibilities included preparation and review of NCS process evaluations; performance and review of NCS calculations and radiation transport calculations; preparation and review of operating procedures; review of process and equipment designs; general operational support; preparation and presentation of NCS training; performance of NCS operational reviews; installation and maintenance of UNIX Workstations; and installation, verification, and maintenance of NCS calculation software on UNIX Workstations and personal computers. Mr. Mueller is proficient in the use of the SCALE computer code package and the MCNP code. He has been a member of the RTC Group since July 2004, where he provides support for burnup credit-related programs in the transportation of spent nuclear fuel. Mr. Mueller’s research interests currently include nuclear criticality safety and burnup credit. He is an active member of the American Nuclear Society (ANS), serves on the ANS Nuclear Criticality Safety Division Program Committee, and is a member of the ANSI/ANS-8.1, “Nuclear Criticality Safety in Operations with Fissionable Materials Outside Reactors,” writing group.