Dosimeter sample preparation, quality assurance, and materials development for the ILRR, FRMDC, and FFTF dosimetry programs

Since the IRML dosimeter program began in 1971, approximately 1900 vanadium encapsulated dosimeters and approximately 100 aluminum encapsulated metal fission foils have been prepared to meet TLRR, FRMDC, and FFTF requirements. Development efforts have focused on cost reduction in fabrication as well as characterization of both pure and dilute materials to meet the desired accuracy goals of +-0.5 and +-1.0 percent (2 sigma), respectively. One important requirement of the dosimeter program is that the dosimeter materials be encapsulated in high purity vanadium. To meet this requirement over the next ten years, an adequate supply of vanadium must be maintained. Efforts were begun to locate and characterize batches of high purity vanadium to meet this requirement. In addition, efforts were initiated to obtain the necssary vanadium capsules, to be fabricated from ILRR material, on a competitive bid basis from a commercial supplier. Quality assurance procedures were established to maintain homogeneity among the various batches of dosimeters produced. Procedures developed for producing the 1.270-mm diameter capsules were adapted to the loading of the more recently required 0.889-mm diameter capsules. Vanadium capsules are to be used in neutron energy spectra, flux and fluence characterization studies during start-up and run phases of the FFTF.