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Application of SN and Monte Carlo Codes to the SHEBA Critical Assemblies

Conference ·
OSTI ID:10167241
 [1]
  1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
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The Solution High-Energy Burst Assembly (SHEBA) at Los Alamos is a low-enriched (4.95 wt. %) aqueous uranyl fluoride solution critical assembly. There are two SHEBA configurations, both consisting of right circular cylinders with a central control rod. The first configuration, hereafter called the old SHEBA, had a fuel solution diameter of 54.6 cm and a measured critical solution height of 36.5 cm. An improved modification, hereafter called the new SHEBA, has a fuel solution diameter of 48.9 cm but since it is not yet operational, the critical solution height has not yet been measured. In this presentation the application of the discrete-ordinates (SN) code TWODANT using Hansen-Roach cross sections and the MCNP Monte Carlo code using continuous-energy cross sections for calculating the critical solution heights for both the old and new SHEBA assemblies is described. The code`s predictions are compared and it is shown that a single calculation with a standard computer code may yield misleading results, especially when using a Monte Carlo code.
Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
10167241
Report Number(s):
LA-UR--93-2258; CONF-931160--7; ON: DE93016560
Country of Publication:
United States
Language:
English

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Related Subjects

050700
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
42 ENGINEERING
420203
97 MATHEMATICS AND COMPUTING
99 GENERAL AND MISCELLANEOUS
990200
AQUEOUS SOLUTIONS
CRITICALITY
CROSS SECTIONS
FUEL ASSEMBLIES
FUELS PRODUCTION AND PROPERTIES
HANDLING EQUIPMENT AND PROCEDURES
M CODES
MATHEMATICS AND COMPUTERS
MCNP
Nuclear Criticality Safety Program (NCSP)
SAFETY
SHEBA Configurations
Solution High-Energy Burst Assembly (SHEBA)
T CODES
TWODANT
URANYL FLUORIDES