Neutronic Analysis For Nuclear Reactor Systems pp 361-385 | Cite as

# Thermal Spectra and Thermal Cross Sections

## Abstract

Although accurate determination of the thermal spectrum also requires advanced computational methods, averages over simplified spectra often serve as a reasonable first approximation in performing rudimentary reactor calculations. The main aspect of nuclear reactor analysis, as we have learned so far, is a multi-group diffusion theory. In previous chapters, we developed the general form of multi-group diffusion equations and recommended a strategy for their solution. However, these set of equations contained various parameters known as group constants formally defined as average over the energy-dependent intergroup fluxed which must be determined before these equations play a formal important roles. In this chapter, we introduce the calculation of neutron energy spectrum characterizing fast neutrons, and as result, the calculation of *fast neutron spectra* as well as generation of *fast group constants* will be of concern. At the conclusion, we will deal with the development of the theory of neutron slowing down and resonance absorption.

## References

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*Neutron Physics*by Karl-Heinrich Beckurts (2013-03-25) Paperback 1656, Published by SpringerGoogle Scholar - 2.E.E. Lewis,
*Fundamentals of Nuclear Reactor Physics*, Published by Academic Press, January 2008CrossRefGoogle Scholar - 3.A.F. Henry,
*Nuclear Reactor Analysis*(MIT Press, New York, NY, 1975)Google Scholar