Determination of $$\overline{η}$$ by Comparison of $$\overline{η}$$σ for U²³⁵ and Pu²³⁹ with $$\overline{η}$$o_a for U²³⁵ in a Flux Critical Assembly Distribution

Technical Report · Tue Apr 05 23:00:00 EST 1960

DOI:https://doi.org/10.2172/4179933· OSTI ID:4179933

Gwin, R. ^[1]; Magnuson, D. W. ^[1]

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1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

The values of $$\overline{η}$$ for U²³³ and $$\overline{η}$$ for Pu²³⁹ have been determined by a reactivity coefficient measurement. An aqueous solution of the isotope was introduced axially into a critical cylindrical annular flux trap reactor, and the resulting reactor change measured by period determinations. From these data the ratio $$\overline{η}$$σ_ax/$$\overline{η}$$σ_a(U²³⁵) was obtained. Using recently measured values of σ_a(U²³⁵) and η for U²³⁵ in this ratio gives the thermal value of 2.308 ± 0.040 for $$\overline{η}$$ of U²³³ and 1.995 ± 0.053 for $$\overline{η}$$ of Pu²³⁹. Correction to a neutron velocity of 2200 m/sec by using the appropriate g-factor gives a value of 2.308 ± 0.040 for η of U²³³ and 2.044 ± 0.054 for η of Pu²³⁹.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP); US Atomic Energy Commission (AEC)
• DOE Contract Number: W-7405-ENG-26
• NSA Number: NSA-14-017345
• OSTI ID: 4179933
• Report Number(s): CF-60-4-11
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPE AND RADIATION SOURCES
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CONFIGURATION
CRITICAL ASSEMBLIES
Critical Assemblies
Criticality
MEASURED VALUES
Measured Values
NEUTRON FLUX
Neutron Flux
Neutron Velocity
Nuclear Criticality Safety Program (NCSP)
PLUTONIUM 239
Plutonium
Plutonium 239
REACTIVITY
RESEARCH REACTORS
SOLUTIONS
THERMAL NEUTRONS
URANIUM 233
URANIUM 235
Uranium
Uranium 233
WATER