Multiregion Concentration Diffusion Coefficient Determination Using Davidon’s Variable Metric Method

Characterization of Delayed-Particle Emission Signatures for Pyroprocessing. Part 1: Fuel Assembly.

“…DG ARs are sensitive to migration effects (Hsue et al, 1978;Tsao and Pan, 1993). Migration exhibits dependence on fuel characteristics and the diffusing species (Hsue et al, 1978;Lee and Durkee, 1984). Our study examines behavior as a function of irradiation.…”

“…(1) the burnup distribution as a function of irradiation and (2) fission-product migration relative to heavy metals. Migration exhibits dependence on fuel characteristics and the diffusing species (Hsue et al, 1978;Lee and Durkee, 1984). It has been reported that 134 Cs and 137 Cs migrate in a similar manner, whereas 95 Zr, 144 Ce, and 154 Eu do not migrate significantly in either the radial or axial directions relative to the heavy metal (Hsue et al, 1978;Pan, 1989;Tsao and Pan, 1993;Dennis and Usman, 2008).…”

SPECT electronic collimation resolution enhancement using chi-square minimization

“…Experience has shown that calculations conducted using noise-free simulated data yield minimized χ 2 ν values that are extremely small, frequently of the order of 10 −15 to 10 −30 , and parameters that are often self-consistent with the generating data to nearly the floatingpoint precision of the computing machine (Lee and Durkee 1985). Such testing provides quite valuable debugging and quality-assurance evaluation for the case in which there should be virtually unambiguous results obtained by the fitting process.…”

“…In this paper we develop a technique that serves to provide enhanced collided-gamma recognition. The technique utilizes the electronic collimation (EC) concept first proposed by Todd (1974) and developed by investigators including Singh (Singh 1983, Singh and Doria 1981, 1983, 1984, 1985, 1988, 1989, Singh and Brechner 1990, Doria and Singh 1982, Brechner et al 1987, Kamae et al (1987) and Dogan et al (1992). The works of Kamae and Dogan pertain to multiple-scatter gammas, thus having the most significant impact on the present work.…”