The Astra testing stand and the critical assemblies simulating on this stand the special physical features of
HTGRs are described. The experimental data, obtained using the Astra stand, on the critical parameters of
assemblies with HTGR fuel pellets and an analysis of the data using the MCU computer program, which
employs the Monte Carlo method, are presented taking account of the requirements of the international
program on critical benchmark experiments. It is shown that the experimental data are in good agreement
with the computational results.
Nuclear power in the future will be characterized by expanded use of nuclear energy for the production of not only
electricity but also high-temperature heat for various technological purposes. High-temperature helium-cooled reactors
(HTGRs), using fuel in the form of particles coated multilayered ceramic coatings and graphite as a moderator and structural
material, are one of the successful solutions meeting these requirements [1, 2].
The technology for this concept is based on many years of experience in designing, developing, and operating high-
temperature reactors in our country and abroad [1–4]. The high helium temperature (850–1000°C) in such reactors makes
possible, together with highly efficient production of electricity, the use of heat for technological purposes, for example, for
obtaining hydrogen from water. This possibility makes nuclear power ecologically much more attractive. Another advantage
is the high temperature potential of the coolant, which makes it possible to decrease heat emissions into the environment and
to use dry cooling towers, providing a measure of flexibility in plant siting because there is no need for cooling water.
The modular type HTGRs (HTGR-M) which are now being developed possess fundamental safety advantages
because the core cannot melt in loss-of-coolant accidents. Such reactors have the following features which influence their
neutron-physical characteristics :
• fuel in the form of particles which are coated with a multilayer coating and placed in a graphite matrix of fuel ele-
ments; this design allows for double heterogeneity in the placement of the fuel in the core and requires that the neutron-phys-
ical calculations be checked against the results of integrated experiments performed with fuel elements of this type;
Atomic Energy, Vol. 97, No. 4, 2004
USING THE MCU COMPUTER PROGRAM
TO ANALYZE THE RESULTS OF
CRITICAL EXPERIMENTS WITH
HTGR FUEL PELLETS ON THE
ASTRA TESTING STAND
N. N. Ponomarev-Stepnoi,
V. I. Bryzgalov, E. S. Glushkov,
E. A. Gomin, M. I. Gurevich,
V. E. Demin, G. V. Kompaniets,
V. A. Lobyntsev, V. I. Nosov,
D. N. Polyakov, O. N. Smirnov,
and O. V. Tel’kovskaya
Russian Science Center Kurchatov Institute. Translated from Atomnaya Énergiya, Vol. 97, No. 4, pp. 243–252,
October, 2004. Original article submitted June 18, 2004.
2004 Springer Science+Business Media, Inc.