Estimation of the Buckling of ²³⁹Pu Fueled System from the Data of Composite ²³⁹Pu-²³⁵U Fueled Fast Critical Assembly

Journal Article · Thu Nov 01 04:00:00 EST 1962 · Nippon Genshiryoku Gakkaishi

OSTI ID:4720544

Ishikawa, H. ^[1]

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1. Japan Atomic Energy Research Inst. (JAERI), Tokai (Japan)

Pu²³⁹- U²³⁵-fueled fast critical assemblies are of interest for the estimation of properties of Pu²³⁹-fueled assemblies because of safety considerations and/or limited plutonium availability. Numerical analysis for bare and reflected homogeneous cores and reflected Two-region cores are previously reported. It is concluded that the errors in the calculated critical size for a 5.0 vol % Pu²³⁹-fueled system reduce by more than a factor of about 10 to 20, if an accurate experimental value of critical size of a critical assembly fueled by 0.5 vol % Pu²³⁹ and 4.5 vol % U²³⁵ is known. A general mathematical formula, which is useful to explain the above conclusions more clearly, is obtained for bare homogeneous mixtures using multigroup diffusion approximation. In order to predict the critical radius for the bare homogeneous Pu system to an accuracy of 1%, the errors for the experimental value of critical radius must be less than 0.1% for ^VPu/^VFuel = 0.05 and 0.2% for ^VPu/^VFuel = where ^VPu and ^VFuel are the volume fractions of Pu²³⁹ and fuel (Pu²³⁹ + U²³⁵) respectively. For the reflected Two region cores, the experimental errors required for the above accuracy must be less than 0.5% for the ratio of central Pu²³⁹ core region volume to total core volume of 0.1.

• Research Organization: Japan Atomic Energy Research Inst. (JAERI), Tokai (Japan)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP); US Atomic Energy Commission (AEC)
• NSA Number: NSA-17-009180
• OSTI ID: 4720544
• Journal Information: Nippon Genshiryoku Gakkaishi, Journal Name: Nippon Genshiryoku Gakkaishi Vol. 4; ISSN 0004-7120
• Publisher: Atomic Energy Society of Japan
• Country of Publication: Japan
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BUCKLING
CRITICAL ASSEMBLIES
CRITICALITY
DIFFUSION
EQUATIONS
ERRORS
FAST NEUTRONS
FUELS
GROUP THEORY
HOMOGENEOUS REACTORS
MATHEMATICS
MIXING
NUMERICALS
Nuclear Criticality Safety Program (NCSP)
PLUTONIUM 239
QUANTITY RATIO
REACTOR CORE
REFLECTORS
SAFETY
URANIUM 235
VOLUME
ZONES