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Title: New probability table treatment in MCNP for unresolved resonances

An upgrade for MCNP has been implemented to sample the neutron cross sections in the unresolved resonance range using probability tables. These probability tables are generated with the cross section processor code NJOY, by using the evaluated statistical information about the resonances to calculate cumulative probability distribution functions for the microscopic total cross section. The elastic, fission, and radiative capture cross sections are also tabulated as the average values of each of these partials conditional upon the value of the total. This paper summarizes how the probability tables are utilized in this MCNP upgrade and compares this treatment with the approximate smooth treatment for some example problems.
Authors:
 [1] ; ; ;  [2]
  1. Carter M.C. Analysis, Richland, WA (United States)
  2. Los Alamos National Lab., NM (United States)
Publication Date:
OSTI Identifier:
658394
Report Number(s):
LA-UR--98-26; CONF-980403--
ON: DE98005277; TRN: 98:011284
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: Radiation protection and shielding topical meeting: technologies for the new century, Nashville, TN (United States), 19-23 Apr 1998; Other Information: PBD: Apr 1998
Research Org:
Los Alamos National Lab., NM (United States)
Sponsoring Org:
USDOE Office of Environmental Restoration and Waste Management, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; 99 MATHEMATICS, COMPUTERS, INFORMATION SCIENCE, MANAGEMENT, LAW, MISCELLANEOUS; M CODES; NEUTRON TRANSPORT; MODIFICATIONS; RESONANCE; N CODES; PROBABILITY; DISTRIBUTION FUNCTIONS; TOTAL CROSS SECTIONS; NEUTRON REACTIONS; NUCLEAR DATA COLLECTIONS; SELF-SHIELDING