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16 Fuel pellet density measurements Measurements will be performed by immersion density or in the Analytical Lab. The im- mersion density apparatus includes an analytical balance equipped with a device to weigh a sample in air and submerged in a liquid generally water. The pycnometer uses a known volume of gas helium to measure the displacement that occurs when the gas is expanded into a closed sample chamber containing the sample. Helium gas penetrates the finest pores thereby assuring maximum accuracy. The volume of the sample is derived from the pressure changes in the system and the ideal gas law. The sample density is calculated by dividing its weight by its volume. The equipment is designed for remote operation using manipulators. The immersion density measurement uncertainty is less than 2. The pyc- nometry measurement accuracy is 2 for sample volumes in the range of 0.2-1 cm3. The instruments are calibrated at the beginning of each day prior to use. The pycnometer and immersion density instrument are validated against a traceable density standard. Tensile tests Axial tensile tests are conducted on the Remote Operated Instron 5869 screw-driven load frame at the HFEF Main Cell Window 13M. This load frame is equipped with an 11250 pound 50 KN capacity primary load cell with option of attaching smaller capacity load cells to allow precision measurement while testing small samples. Crosshead displacement speed can be varied from 0.00004 inmin 0.001 mmmin to 20 inmin 500 mmmin. With an available test space of approximately 47.4 inches 1205 mm vertical by 37 inches 940 mm horizontal a variety of testing setups can be accommodated. The high force capacity load cell combined with adaptable fixturing allows tensile testing of a variety of American Society for Testing and Materials ASTM standard and nonstandard speci- mens as well as other tests requiring controlled application of tensile or compressive force such as bend tests or flexure tests. Currently this load frame is not capable of direct strain measurements and crosshead displacement corrected by measured machine compliance is used to infer strain. An attached furnace capable of 1200 C operation allows high-tem- perature testing. Current plans include addition of a multizone furnace to allow more precise control of temperature for larger specimens and installation of an extensometer to allow direct strain measurement.