Authors & Affiliations

Seleznev E.F., Bereznev V.P., Chernova I.S.
Nuclear Safety Institute of the Russian Academy of Sciences, Moscow, Russia

Seleznev E.F. – Head of Laboratory, Senior Researcher, Dr. Sci. (Techn.), Nuclear Safety Institute of the Russian Academy of Sciences. Contacts: 52, Bolshaya Tulskaya st., Moscow, Russia, 115191. Tel.: +7 (495) 955-23-11; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..
Bereznev V.P. – Researcher, Cand. Sci. (Techn.), Nuclear Safety Institute of the Russian Academy of Sciences.
Chernova I.S. – Junior Researcher, Nuclear Safety Institute of the Russian Academy of Sciences.

Abstract

Solutions of the partial neutron transport equations, being components of the neutron flux density, which is usually measured by ionization chambers, would seem to not be fixed experimentally. But ionization chambers can be created on the basis of various fissile materials, including those having a threshold fission cross section, which is used in experiments on active reactors to “filter” the signal from the background, when, for example, the signal in the chamber is used only on the basis of high-energy neutrons eliminate taking into account the ionization of the gas medium in the ionization chamber from gamma-quanta, i.e. exclude the background.
Such ionization chambers include cameras based on the use of 232Th, 238U, 236U, 237Np, 234U with a fission threshold energy of 1.5, 1.3, 0.70, 0.32 and 0.26 MeV, respectively. Together with the use of a 235U non-threshold chamber, these chambers offer the possibility of obtaining some experimental estimates of the partial solutions of the neutron transport equations in a fast neutron reactor.
At the same time, the use of a threshold ionization chamber that records only a fraction of the neutrons from their full spectrum during a non-stationary process in a reactor with a change in the fraction of delayed neutrons in it, i.e. amplification of one or another part of the neutron spectrum may not fully take into account these changes and, thus, increase the measurement error. The possibility of estimating the magnitude of such an error is given by partial solutions of the neutron transport equations.

Keywords
partial equations, reactor, prompt neutrons, delayed neutrons, spectrum, ionization chamber, thresh-old chamber, experimental, reactivity, rod efficiency, kinetics

Article Text (PDF, in Russian)

References

UDC 621.039

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2019, issue 3, 3:15