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Title: PACER-IBM: A two dimensional Monte Carlo multigroup program for the IBM personal computer

Technical Report ·
OSTI ID:6964756

PACER-IBM is a Monte Carlo computer program written in BASIC at Bettis for the IBM personal computer. This program is capable of solving simple two dimensional neutron transport problems in X - Y geometry. The space - energy neutron flux distribution over the energy range of 10 MeV to 0 eV is calculated using fixed source starts within the source regions of the solution geometry. PACER-IBM accesses multigroup cross sections which have been prepared using the CDC-7600 program RCPL1, a program to prepare neutron and photon cross section libraries for RCP01, and down loaded from the CDC-7600. Neutron behavior in the PC program is simulated by a random walk, a process that is identical to that used in the CDC-7600 Monte Carlo program PACER. A neutron's location in phase space, i.e.., its position, direction, and energy is selected randomly and the neutron is tracked through the solution geometry (in free flight) until a collision occurs. In the collision analysis new neutron direction and energy are selected randomly based upon probabilities determined from basic neutron cross section data. The tracking process and the collision analysis is continued until a termination event, such as absorption, leakage, or slowing down below a specified energy, occurs. The set of calculations for one neutron from source to termination is called a neutron history. A large number of histories is processed to estimate the space-energy neutron flux. Comparisons of results with CDC-7600 PACER solutions are favorable for several two dimensional test problems. 2 refs.

Research Organization:
Bettis Atomic Power Lab., West Mifflin, PA (USA)
DOE Contract Number:
AC11-76PN00014
OSTI ID:
6964756
Report Number(s):
WAPD-T-2889; ON: DE87002703
Resource Relation:
Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English