CRITICAL-ASSEMBLY STUDIES ON AN INTERMEDIATE REACTOR FOR AIRCRAFT PROPULSION

Technical Report · Mon Jul 15 04:00:00 EDT 1957

OSTI ID:4718514

Marinaccio, L F; Jung, R G; Jankowski, F J; Dingee, D A; Chastain, J W

Critical-assembly experiments on a solid-fuel reactor system were performed. The prototype reactor was fueled by a UO/sub 2/-stainless steel dispersion, sodium cooled, beryllium or BeO moderated and reflected, and controlled by rotating drums, containing B/sub 4/C over a 120-deg sector, located in the radial reflector. The critical-assembly mocks up this system using beryllium blocks for moderator, uranium foils for fuel, stainless steel foils to simulate structure and cladding, aluminum to simulate sodium, and B/sub 4/C filled tubes positioned to simulate the control drums. Control of the critical assembly was achieved by moving fuel and separating the core into two sections. Experiments were performed to determine the critical mass and the complete power distribution for the two extreme positions of the control drums: poison completely in, called the 0-deg position, and poison rotated all out, called the 180-deg position. Curves of the radial and axial power distributions for these cases are presented. Detailed power-distribution measurements within simulated fuel elements are included. The critical masses were 69.00 and 50.78 kg for the 0- and 180-deg controldrum positions, respectively. From the power-distribution measurements the peak-to-average power ratios were obtained. Individual fuel elements have a maximum radial peak-to-average power ratio of 1.21 and an element ratio of 1.56. The power-distribution measurements show the axial and radial functions representing power to be separable within the accuracy of the experiments. Dangercoefficient measurements were made for several materials. The dollar unit of reactivity was calculated to be 0.0085. From the reactivity worth of the uranium-235 and the change in critical mass on rotating the critical- assembly control drums, the prototype power-reactor control was estimated to have a reactivity worth of 97 or 7.62%. For the critical assembly, each of the two regulator rods was worth approximately 3 cents; one safety rod was worth from 16.8 to 21.5 cents; all safety rods were worth from 68 to 15; and the table gap was worth from 50 to 68 in reactivity for the first inch separation. (auth)

• Research Organization: Battelle Memorial Inst., Columbus, Ohio
• DOE Contract Number: W-7405-ENG-92
• NSA Number: NSA-17-026846
• OSTI ID: 4718514
• Report Number(s): BMI-1209
• Country of Publication: United States
• Language: English

Related Subjects

AIRCRAFT
ALUMINUM
BERYLLIUM MODERATOR
BERYLLIUM OXIDES
BORON CARBIDES
CONTROL ELEMENTS
CONTROL SYSTEMS
CRITICAL ASSEMBLIES
CRITICALITY
DIAGRAMS
DISPERSIONS
DISTRIBUTION
FOILS
FUEL ELEMENTS
LIQUID METAL COOLANT
MASS
MEASURED VALUES
MOCKUP
POISONING
POWER
POWER PLANTS
PROPULSION
REACTIVITY
REACTOR CORE
REACTOR SAFETY
REACTOR TECHNOLOGY
REFLECTORS
SODIUM
STAINLESS STEELS
TUBES
URANIUM
URANIUM 235
URANIUM DIOXIDE
ZONES