Science Letter
December 8, 2009

ATOMIC SCIENCE;
Findings from V.G. Petrosyan and co-authors provide new insights into
atomic science

"The nonlinear dynamic auto-oscillatory regimes of the temperature at
the exit from the core and of the power of nuclear reactors are
investigated and the quantitative features of the regimes are
determined. A physical-mathematical model of the dynamics of a
VVER-type nuclear reactor is examined, taking account of the inertial
(temperature) and instantaneous (power) feedbacks in the reactor but
neglecting the delayed neutrons," scientists in Yerevan, Armenia
report (see also Atomic Science).

"Analytical solutions characterizing the auto-oscillatory real-time
behavior of the temperature at the exit from the core and of the
reactor power are obtained. The period of these oscillations is
determined. The model constructed for the dynamics of a reactor is
used as a basis to simulate, using the RELAP5/Mod3.2 computer code,
certain nonlinear auto-oscillatory processes occurring in the first
and second loops of a nuclear power plant with a VVER-440 reactor,"
wrote V.G. Petrosyan and colleagues.

The researchers concluded: "It is found that the oscillations of the
temperature at the exit from the core and power of the nuclear reactor
generate the same period for processes which were calculated."

Petrosyan and colleagues published their study in Atomic Energy
(MODELING THE NONLINEAR DYNAMIC TEMPERATURE AND POWER OSCILLATIONS IN
VVER. Atomic Energy, 2009;107(1):18-23).

For additional information, contact V.G. Petrosyan, Armatom Research
Institute, Yerevan, Armenia.

The publisher’s contact information for the journal Atomic Energy is:
Springer, 233 Spring St., New York, NY 10013, USA.