Feasibility of /sup 3/HeD/sup 6/LiD thermal-to-fusion neutron converters for fusion reactor materials testing

Abstract

3HeDf'LiD thermal-to-fusion (E=14 MeV) neutron converters have been developed at the IWW-2M reactor to simulate the irradiation of structural materials in a fusion reactor. These converters increase the highest energy part of the neutron spectrum (E > 14 MeV) by =10lo n/ (cm2*s) in the reactor's test channel (=6-cm dim.), corresponding to a 14-MeV neutron fluence of =2*1016 dcm' per 500-hour reactor cycle. However, the high energy release (up to 1-2 kW/gr) in the converters from the 6Li(n,T)a and 3He(n,T)p exothermal reactions created there can be a critical problem in conducting experiments of this kind.

Efficiency measurement of converter of thermal to fast neutrons of (DT), () fusion with 14 MeV energy in IVV-2M reactor experimental channel

“…At that, practically accurate account was taken of the measuring trays construction and the mentioned non-uniform spatial distribution of fusion neutron sources (2,3) in the bulk of the converting layers. Angular distribution of fusion neutrons in MTs was taken as isotropic, and their energy distribution, as per the calculations given in [10].…”

“…In this connection, it may be interesting to consider the suggestion discussed in [2] of using the 6 LiD solid-state converter for converting thermal neutrons in the channel of the IVV-2M high-flux fission reactor [3] to fast neutrons with energy E ∼ = 14 MeV as a result of (na) reactions on 6 Li nuclei with formation of fast tritium nuclei ( ∼ = 2.74 MeV): 6 Li + n → T + 4 He (q ∼ = 4.79 MeV, σ T ∼ = 950 b) (1) and subsequent reactions of tritium nuclei fusion with deuterium and lithium-6 nuclei:…”

“…According to the definition accepted in [8], efficiency (K) of 6 LiD converter of thermal to fast 14 MeV neutrons is characterized by the relation of ratesṄ D , N Li of fusion neutrons generation (2,3), respectively, to rateṄ T of thermal neutrons absorption in the converting layer:…”