TY - JOUR

T1 - Investigation of (n, 2n) reaction and fission rates in iron-shielded uranium samples bombarded by 14.9 MeV neutrons

AU - Shani, Gad

PY - 1976/1/1

Y1 - 1976/1/1

N2 - The effect of the thickness of iron shielding on the (n, 2n) reaction rate in a fusion reactor (hybrid) blanket is investigated. The results are compared with the fission rate-dependence. Samples of natural uranium where irradiated with 14 MeV neutrons with iron slabs of various thickness between the neutron generator target and the samples. Both reactions are threshold reactions but the fact that the 238U (n, 2n) reaction threshold is at 6 MeV and that of fission is at 2 MeV makes the ratio between the two very much geometry-dependent. Two geometrical effects take place, the 1 r2 and the build-up. While the build-up affects the (n, 2n) reaction rate, the fission rate is affected more by the 1 r2 effect. The reason is that both elastic and inelastic scattering end up with neutrons with energy above fission threshold, while only elastic scattering brings high energy neutrons to the sample and cause (n, 2n) reaction. A comparison was made with calculated results where the geometrical effects do not exist.

AB - The effect of the thickness of iron shielding on the (n, 2n) reaction rate in a fusion reactor (hybrid) blanket is investigated. The results are compared with the fission rate-dependence. Samples of natural uranium where irradiated with 14 MeV neutrons with iron slabs of various thickness between the neutron generator target and the samples. Both reactions are threshold reactions but the fact that the 238U (n, 2n) reaction threshold is at 6 MeV and that of fission is at 2 MeV makes the ratio between the two very much geometry-dependent. Two geometrical effects take place, the 1 r2 and the build-up. While the build-up affects the (n, 2n) reaction rate, the fission rate is affected more by the 1 r2 effect. The reason is that both elastic and inelastic scattering end up with neutrons with energy above fission threshold, while only elastic scattering brings high energy neutrons to the sample and cause (n, 2n) reaction. A comparison was made with calculated results where the geometrical effects do not exist.

UR - http://www.scopus.com/inward/record.url?scp=49549130442&partnerID=8YFLogxK

U2 - 10.1016/0306-4549(76)90027-X

DO - 10.1016/0306-4549(76)90027-X

M3 - Article

AN - SCOPUS:49549130442

VL - 3

SP - 431

EP - 435

JO - Annals of Nuclear Energy

JF - Annals of Nuclear Energy

SN - 0306-4549

IS - 9-10

ER -