XENON AND SAMARIUM CONCENTRATIONS PRODUCED BY VARIOUS FLUX PROGRAMS
The effect of time variations of the flux on the Xe/sup 135/ and Sm/sup 149/ concentrations in a reactor is discussed in this paper. The large increase in poison concentration following a reduction of flux is given ns a function of time for various initial and final values of the flux. Graphs are provided from which the maximum xenon and samarium concentrations following a reduction of flux from any initial to any flnal value can be determined. For the special case of reduction to zero flux the effect of various initial conditions on the resulting xenon concentration is shown as a function of time. The reactivity required for criticality is given as a function of xenon concentration, samarium concentration, and reactor constants. Also, the effect of the spacial dependence of poison concentration on reactivity calculations is briefly discussed. The problem of maintalning criticality during the shutdown of a reactor which cannot override maximum poison concentration is investignted. The poison concentration produced by periodic time variations in the flux is determined as a function of time for various frequencies and amplitudes of oscillation. Also, the variation in poison concentration produced by an arbitrary flux problem is discussed briefly. Appendix I enables solution of the more general problem, that of xenon and samarium buildup from arbitrary initial concentrntions. Appendix II discusses the problem of the time vsriations of poison concentrations produced by an increase of the flux level. (auth) 13495 The results of a preliminary study of building inherent control into a pressurized water reactor,''steam rod'' partially confined channels in parallel with the coolant channels, but closed at the top. Forced convection flow does not occur through these partially enclosed chambers; hence, steam is generated. The design of the core is such that the system is supercritical when all these chambers sre filled with water, and subcritical when they are all filled with steam. When criticality is achieved, all chambers contain some proportion of steam and water. The relative amounts of steam and water act as a control of reactivity. (W.L.H.)
- Research Organization:
- Westinghouse Electric Corp. Atomic Power Div., Pittsburgh
- DOE Contract Number:
- AT(11-1)-GEN-14
- NSA Number:
- NSA-12-013494
- OSTI ID:
- 4332985
- Report Number(s):
- WAPD-RM-182(Del.)
- Country of Publication:
- United States
- Language:
- English
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