The High Flux Isotope Reactor at the Oak Ridge National Laboratory provides the highest steady-state thermal neutron flux in the western world for a wide range of experiments and for isotope production. The highest available fluxes are located in a flux trap region created inside the nested fuel elements. The experimentally determined thermal and the empirically obtained epithermal flux values along the vertical axis of the peripheral target position were fit to cosine curves, with the thermal flux ranging from 1.1 x 10(15)ns(-1)cm(-2) at outer positions to 1.5 x 10(15)ns(-1)cm(-2) at the center. The corresponding epithermal flux ranged from 3.5 x 10(13) to 7.5 x 10(13)ns(-1)cm(-2), respectively. The fast neutron flux (En > or = 0.32 MeV in two positions and En > or = 1.5 MeV in two other positions) was approximately 6 x 10(14)ns(-1)cm(-2), corresponding to a fast to thermal ratio of approximately 0.4.

On July 18, 1996, the Oak Ridge National Laboratory (ORNL) resumed shipping spent fuel in interstate commerce after a 10 year suspension of this activity. This shipment was conducted using a Nuclear Regulatory Commission licensed spent fuel transport package purchased from General Electric Company by ORNL for the purpose of moving High Flux Isotope Reactor spent fuel to the Savannah River Site. The trailer, fabricated to the ANSI N14.30, Semi-Trailers Employed in the Highway Transport of Weight Concentrated Radioactive Loads Design, Fabrication, and Maintenance, has recently undergone its first scheduled in-service inspection. This paper presents the experience gained from interpretation and application of the ANSI N14.30 standard focusing on the in-service inspection for the structure of the trailer. Initially, the term weight concentrated is illustrated giving detail to the location and center of gravity of the 33,500 pound shipping container and forces induced by the tie down system. Basic information about the design stresses and initial testing provided by the manufacturer are used as a lead-in to the requirements of the standard. The task of examining the trailer structure provided many lessons and required considerable effort. All of the support personnel were provided by ORNL; the garage mechanics and themore » certified inspection engineers had never been involved in applying ANSI N14.30. Other obstacles were the lack of existing inspection procedures for this particular activity and the lack of a previous experience interpreting the standard with regard to repair work. Some of these questions were resolved by clarification received from the writers of the standard, and others were resolved by the teamwork between the manufacturer and ORNL. This experience illustrated the importance of the trailer manufacturer as a participant in the decisions made concerning in-service inspection and maintenance.« less