ANALOG SIMULATION OF XENON INSTABILITY

Technical Report · Fri Jan 20 04:00:00 EST 1961

OSTI ID:4064315

Pearce, R M

Spatial oscillations in ths flux of a power reactor, caused by xenon and temperature effects, are studied on a generalpurpose electrical analog computer. The linearized forms of the two-group diffusion equation are solved in one dimension using finite space interwals. The linearized forms of the iodine and xenon equations are solved using continuous integration. Good agreement is obtained with predictions from other theories in simple cases. In the case of a large uniform reactor with a threshold fiux for oscillation well below 10/sub 1/)/ sup 3/, the oscillating portions of the fast and slow flux distributions and of the xenon and iodine distributions all have the same shape in space. For smaller reactors with toresholds above 10/sup 19/, the fluxes and iodines retain their space shape during a cycle when only the lowest mode is excited, but the oscillating pant of the xenon changes shape during a cycle. This is a result of the xenon lifetime's varying through the neactor. At a central flux of 2.1 x 10/ sup 14/, the maxima in the xenon occur 2.5 hr later at the outside of a cylinder than at the center. Some examples of mode shapes ane given for reflected reactors. A twogroup study of the first azimuthal mode of CANDU at three powers and several prompt power ccefficients appears to indicats that the mode is damped. (auth)

• Research Organization: Atomic Energy of Canada Ltd., Chalk River, Ont.
• NSA Number: NSA-15-013912
• OSTI ID: 4064315
• Report Number(s): CRRP-998; AECL-1185
• Country of Publication: Canada
• Language: English

Related Subjects

ANALOG SYSTEMS
CANDU
COMPUTERS
DIFFUSION
DISTRIBUTION
FAST NEUTRONS
GROUP THEORY
HALF-LIFE
IODINE
LIFETIME
NEUTRON FLUX
OSCILLATIONS
POWER
POWER COEFFICIENT
REACTIVITY
REACTOR TECHNOLOGY
REACTORS
REFLECTION
SIMULATORS
STABILITY
TEMPERATURE
THERMAL NEUTRONS
TRANSPORT THEORY
XENON
ZONES