EDN: HEZECI
Authors & Affiliations
Isachenkov I.A., Alekseev P.A.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia
Isachenkov I.A. – Research Engineer. Contacts: 1, pl. Bondarenko, Obninsk, Kaluga region, Russia, 249033. Tel.: +7 (484) 399-70-00 (add. 51-16); e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..
Alekseev P.A. – Leading Researcher, Dr. Sci. (Tech.).
Abstract
The paper presents a computational and theoretical study of 225Ac production using a photonuclear reaction in VVR-ts reactor. A mixed 226Ra and 157Gd target is placed in the reactor core. 157Gd has a large neutron capture cross-section in thermal energy range. The result of the reaction is high-energy γ-photons which interact with 226Ra to produce 225Ra according to 226Ra(γ, n)225Ra. The produced 225Ra decays into 225Ac. After irradiation and decay 225Ac can be extracted.
The calculation of the γ-photons spectrum showed that the contribution of γ-photons produced by 157Gd exceeds γ-photons of the reactor in the energy range 6–10 MeV required for photonuclear reaction.
The reaction rate of 225Ra production calculation included two stages. In the first stage we used 3D heterogeneous model of VVR-ts reactor to record neutron tracks on inner cylindrical surface of experimental assembly for surface neutron source.
In the second stage we used surface source to calculate the 225Ra production rate for different 157Gd concentrations in the target excluding reactor geometry. To estimate 225Ac production rate during both irradiation and decay we applied radioactive decay equations.
In addition to 225Ra neutron interactions with 226Ra generate 227Ra which later decays into 227Ac. Presence of 227Ac in radiopharmaceuticals exclude use for medical application.
Calculation results for VVR-ts reactor showed that it is possible to produce 5.10 mCi of 225Ac and 104.46 mCi of 227Ac for 31 days of irradiation and 17 days of decay.
Keywords
photonuclear reaction, reaction cross-section, VVR-ts reactor, actinium-225, actinium-227, gadolinium-157
Article Text (PDF, in Russian)
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UDC 621.039.8.002
Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2026, no. 1, 1:13
