The equivalent, fundamental-mode source

Technical Report · Tue Dec 24 04:00:00 EST 1996

DOI:https://doi.org/10.2172/441771· OSTI ID:441771

Spriggs, G D ^[1]; Busch, R D ^[2]; Sakurai, Takeshi; Okajima, Shigeaki ^[3]

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1. Los Alamos National Lab., NM (United States)
2. Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering
3. Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)

In 1960, Hansen analyzed the problem of assembling fissionable material in the presence of a weak neutron source. Using point kinetics, he derived the weak source condition and analyzed the consequences of delayed initiation during ramp reactivity additions. Although not clearly stated in Hansen`s work, the neutron source strength that appears in the weak source condition actually corresponds to the equivalent, fundamental-mode source. In this work, they describe the concept of an equivalent, fundamental-mode source and they derive a deterministic expression for a factor, g*, that converts any arbitrary source distribution to an equivalent, fundamental-mode source. They also demonstrate a simplified method for calculating g* in subcritical systems. And finally, they present a new experimental method that can be employed to measure the equivalent, fundamental-mode source strength in a multiplying assembly. They demonstrate the method on the zero-power, XIX-1 assembly at the Fast Critical Assembly (FCA) Facility, Japan Atomic Energy Research Institute (JAERI).

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 441771
• Report Number(s): LA-UR--97-1; ON: DE97003470
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
CRITICALITY
FCA REACTOR
MEASURING METHODS
MULTIPLICATION FACTORS
NEUTRONS
REACTIVITY
REACTOR KINETICS