Statistical Fluctuations in Reactors; FLUCTUATIONS STATISTIQUES DANS LES PILES

Technical Report · Fri Jan 01 04:00:00 EST 1960

OSTI ID:4077418

Raievski, V

The theory of space-dependent fluctuations is developed, taking into account the effect of delayed neutrons. The "diffusion equation" or Fokker- Planck equation is worked out in the case of age and two-group theory, but the first one because of its physical significance is used in this report. The theory is applied to the study of the spectral density of fluctuations ard fluctuations of counting rate and current flowing through the charge resistor of an ionization chamber; the effect of the entrance capacity is discussed. The space-dependent theory shows that the fluctuations in the core and reflector of a near-critical pile obey the same law. The spectral densities in the core and reflector are similar; there is no sensible attenuation of high-frequency fluctuations in the reflector. Compared to the space-independent theory, this theory gives better agreement with experience. One can use the simple space- independent theory but in checking with experiment it is necessary to introduce numerical factors given by the space-dependent theory. (auth)

• Research Organization: France. Commissariat a l'Energie Atomique. Centre d'Etudes Nucleaires, Saclay
• NSA Number: NSA-15-012455
• OSTI ID: 4077418
• Report Number(s): CEA-1673
• Country of Publication: France
• Language: English

Related Subjects

CRITICALITY
CURRENTS
DELAYED NEUTRONS
DIFFERENTIAL EQUATIONS
DIFFUSION
FOKKER-PLANCK EQUATION
GROUP THEORY
IONIZATION CHAMBERS
LIFETIME
MATHEMATICS
NEUTRON DETECTION
REACTIVITY
REACTOR CORE
REACTOR TECHNOLOGY
REACTORS
REFLECTORS
RESISTORS
SPECTRA
STATISTICS
TRANSPORT THEORY
VARIATIONS
ZONES