Certain experiments involving irradiation of samples in nuclear reactors, specially those for studies in biology, chemistry, physics and materials science where alteration of properties are to be induced by fast neutrons, require the knowledge of the neutron spectrum, particularly in order to calculate the doses absorbed by the samples on the basis of averaged kerma factors. Aiming at a general characterization of the fast neutron spectrum at the irradiation facilities of the Portuguese Research Reactor - a 1 MW pool type reactor, with fuel elements of MTR shape -, in a way which does not depend on the core configuration and on the irradiation conditions, the following simplified calculation was carried out: 1) the face of the reactor core has been considered as being a uniform plane source of fission neutrons, and 2) using the MCNP-4A code, the spectrum of fast neutrons has been calculated at several distances along the central axis normal to the source, considering various combinations of diffusing media of various thickness.

Date Published: 27 February 1997
PDF: 4 pages
Proc. SPIE 2867, International Conference Neutrons in Research and Industry, (27 February 1997); doi: 10.1117/12.267952

Published in SPIE Proceedings Vol. 2867:
International Conference Neutrons in Research and Industry
George Vourvopoulos, Editor(s)