One-Group Perturbation Theory Applied to Measurements with Void
Persson, Rolf
42 ENGINEERING; VOIDS; BUCKLING; NEUTRON FLUX; PERTURBATION THEORY
Formulas suitable for evaluating progressive as well as single rod substitution measurements are derived by means of one-group perturbation theory. The diffusion coefficient may depend on direction and position. By using the buckling concept one can derive expressions which are quite simple and the perturbed flux can be taken into account in a comparatively simple way. By using an unconventional definition of cells a transition region is introduced quite logically. Experiments with voids around metal rods, diam. 3.05 cm, have been analysed. The agreement between extrapolated and directly measured buckling values is excellent, the buckling difference between lattices with water-filled and voided shrouds being 0. 263 {+-} 0.015/m{sup 2} and 0.267 {+-} 0.005/m{sup 2} resp. From single-rod experiments differences between diffusion coefficients are determined to {delta}D{sub r}/D = 0.083 {+-} 0.004 and {delta}D{sub z}/D = 0.120 {+-} 0.018. With air-filled shrouds there is consequently anisotropy in the neutron diffusion and we have (D{sub z}/D{sub r}){sub air} = 1.034 {+-} 0.020.
AB Atomenergi, Nykoeping (Sweden)
Commercial reproduction prohibited; OSTI as DE20949482
Sweden
1966-09-15
English
Technical Report
Other Information: 3 refs., 5 figs., 4 tabs.
Miscellaneous
Medium: ED; Size: 26 pages
AE-248
TRN: SE0708459
SWDN
2018-03-26
20949482
https://www.osti.gov/etdeweb/servlets/purl/20949482