Date of Award

3-1993

Document Type

Thesis

Degree Name

Master of Science in Nuclear Engineering

Department

Department of Engineering Physics

First Advisor

Richard S. Hartley, PhD

Abstract

The neutron spectrum unfolding code BUNKI, developed at the Naval Research Laboratory in 1983, was modified to incorporate a finer energy group structure, seven initial-guess spectra, and new dose conversion factors. The modified code, AFITBUNKI, unfolds spectra into 54 energy groups between 10-7 and 14.92 MeV. The code calculates fluence, absorbed dose, percent of effective dose equivalent, and percent of ambient dose equivalent as a function of neutron energy. Additionally, AFITBUNKI calculates total energy-integrated fluence (Φ), absorbed dose (D), dose equivalent (H), effective quality factor (Q), ambient dose (D*), both ICRP Publication 26- and ICRP Publication 60-based ambient dose equivalent (H*) and effective ambient quality factor (Q*), effective dose equivalent (HE), effective dose (-E), and the average neutron energy (E). AFITBUNKI uses BUNKI's SPUNIT iterative unfolding algorithm and UTA54, the 171-energy group response matrix developed at The University of Texas at Austin using ENDF/B-IV cross sections collapsed into the 54-group structure. The modified code is verified against spectra unfolded by BUNKIUT and validated against calculations of a NIST fit of 252Cf fission neutrons and against calculations of both D2O- and polyethylene-moderated 252Cf fission neutrons made by Los Alamos National Laboratory's Monte Carlo Neutron-Photon transport code, MCNP.

AFIT Designator

AFIT-GNE-ENP-93-M-5

DTIC Accession Number

ADA262358

Comments

The author's Vita page is omitted.

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