Calculation of the effective delayed-neutron fraction and prompt-neutron lifetime in IBR-2M

• Published in: Atomic energy (New York, N.Y.) N.Y.), 2011-12, Vol.111 (2), p.122-126
• Main Authors: Pepelyshev, Yu. N., Rogov, A. D., Taiybov, L. A., Min, Jang Chang, Mekhtieva, R. N.
• Format: Article
• Language: English
• Subjects: Accuracy; Approximation; Atomic energy; Codes; Constants; Decay; Energy; Error analysis; Errors; Hadrons; Heavy Ions; International; Mathematical analysis; Neutrons; Nuclear Chemistry; Nuclear Energy; Nuclear Physics; Nuclear power generation; Nuclear reactors; Physics; Physics and Astronomy; Studies; Systems design; Two dimensional
• ISSN: 1063-4258; 1573-8205
• DOI: 10.1007/s10512-011-9463-8

The main parameters of IBR-2M are presented: the effective delayed-neutron fraction β eff and the promptneutron lifetime τ, calculated using the DORT two-dimensional multigroup neutron-transport compute code and the SCALE4 code with a system of multigroup nuclear constants. For a regular IBR-2M regime β eff  = 0.00216 ± 0.00007, τ = (6.5 ± 0.5)·10 –8 sec, the delay-neutron value γ = 0.980, the prompt-neutron decay constant in the critical state α = 3.5·104 sec –1 . The calculations showed that the effective delayed-neutron fraction for IBR-2M is identical, within the error limits, to the measured value for IBR-2, the prompt-neutron lifetime is approximately 5% longer (β eff  = 0.00216, τ = (6.2 ± 0.2)·10 –8 sec). It is shown that β eff and τ increase somewhat as the IBR-2 core size increases in the radial direction.