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Criticality data and validation studies of mixed-oxide fuel pin arrays in Pu+U+Gd nitrate

Journal Article · · Nuclear Technology; (United States)
OSTI ID:6903597
 [1];  [2];  [3]
  1. Oak Ridge National Lab., TN (United States). Computing and Telecommunications Div.
  2. Pacific Northwest Lab., Richland, WA (United States)
  3. Power Reactor and Nuclear Fuel Development Corp., Tokyo (Japan)
Critical experiments were performed at the Pacific Northwest Laboratory's Critical Mass Laboratory in 1987 and 1988 with a heterogeneous array of mixed-oxide (MOX) fuel pins immersed in mixed plutonium-uranium nitrate solutions. The 996 fuel pins, on a 1.40-cm-square pitch, were configured in a cylindrical array. The solution heavy metal concentrations ranged from 4 to 468 g/[ell] and had a Pu/Pu + U ratio of 0.2. Critical experiments were also performed with gadolinium added to the fissile solution. These experiments were designed to simulate conditions in a MOX fuel dissolver, where fuel lumps are moderated by aqueous solutions containing fissile nuclides, with and without a soluble neutron poison. For the experimental conditions examined, it was determined that the critical size of the system increased as the heavy metal concentration increased. The criticality data were used to validate two versions of the scale computer code system and the 27-energy-group cross-section library, derived from the Evaluated Nuclear Data File B Version IV. The calculations results indicate that SCALE-2 has some difficulty in modeling these systems. Modifications in SCALE-4 have led to more accurate K[sub eff] results.
DOE Contract Number:
AC05-84OR21400
OSTI ID:
6903597
Journal Information:
Nuclear Technology; (United States), Journal Name: Nuclear Technology; (United States) Vol. 107:3; ISSN 0029-5450; ISSN NUTYBB
Country of Publication:
United States
Language:
English