A problem in the teaching of reactor kinetics
- Reed College, Portland, OR 97202 (United States)
All textbooks on reactors point out that the 1-equivalent-delayed-group approximation to the Point Kinetics Equations, produces results qualitatively similar to the behavior of a reactor with 6 delayed-neutron groups. Furthermore, they take pains to illustrate that the 1-equivalent-group equations are analytically soluble for certain simple forms of reactivity change. Unfortunately, all authors have slavishly followed the authors of the 1st such textbook (H. Soodak and E.C. Campbell) by always solving the same inappropriate problem which involves a step reactivity change in a system with no reactivity feedback and no steady neutron source. In this 'classic' problem, the system is initially perched precariously at a single point in k-space, i.e. k=1, and a change causes the neutron density either to diverge exponentially or to decay away to zero. Only 1 balanced bank of the control rods is predicted to produce a steady-state condition. Experimentally, the student soon finds that many combinations of balanced-bank settings lead to a steady state, and that a decrease of reactivity, starting from a steady state, leads only to a new steady state of lower power. Evidently, the classic model does not match experience, even qualitatively. However, the match is vastly improved if the steady source is incorporated into the Point Kinetic Equations. It is the plea of this author that future textbook writers discuss the more practical situation, i.e. that in which a source is present.
- Research Organization:
- General Atomics, San Diego, CA (United States)
- OSTI ID:
- 21141225
- Report Number(s):
- INIS-US-09N0043; TOC-23; TRN: US09N0071020862
- Resource Relation:
- Conference: 12. U.S. TRIGA users conference, Austin, TX (United States), 11-14 Mar 1990; Other Information: Country of input: International Atomic Energy Agency (IAEA); 6 refs; 3 figs; Related Information: In: 12. U.S. TRIGA users conference. Papers and abstracts, 328 pages.
- Country of Publication:
- United States
- Language:
- English
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