PROSPECTS FOR PRODUCTION OF STRUCTURAL
GRAPHITES FOR NUCLEAR POWER ENGINEERING
AND OTHER SECTORS OF INDUSTRY
AT THE CHELYABINSK ELECTRODE PLANT JOINT-STOCK Co.
A. A. Sviridov,
S. A. Podkopaev,
N. P. Nonishneva,
A. Yu. Zheleznyak,
Yu. S. Virgil’ev,
and A. N. Seleznev
Translated from Novye Ogneupory, No. 8, pp. 6 – 10, August, 2004.
Original article submitted June 23, 2004.
The results of a study of the properties of VPG-grade reactor graphite based on calcined pitch coke currently
used as an alternative to KNPS-grade petroleum coke are reported. Technologies for production of new
high-density fine-grained graphites based on calcined pitch coke and uncalcined pitch and resin cokes have
been developed. Different shaping techniques — extrusion and hot pressing — have been tested. The newly
developed high-density fine-grained graphites display superior physicomechanical properties and can be used
for service in modified high-capacity reactors.
The Chelyabinsk Electrode Plant (ChEP) JSC is a tradi-
tional manufacturer of a wide range of graphite materials for
use in different sectors of industry, including nuclear power
engineering. The raw material for these graphites was a spe-
cial pyrolysis petroleum coke (KNPS-grade) available from
Volgograd Oil Refinery. For technical and economic reasons,
the coke production was suspended in 1994 and the produc
tion of structural graphites was also stopped. This had a seri
ous impact on the safe operation of nuclear power plants,
considering that there was no longer a supply of repair rings
and solid contact sleeves made of VPG-grade graphite for
RBM-K (light water graphite-moderated reactor)-type reac
tors and V-16 graphite sleeves for industrial reactors.
Thus, finding an alternative to KNPS coke and develop
ing an adequate technology has become a matter of urgent
concern for specialists.
The coke, a candidate alternative to KNPS petroleum
coke for production of reactor graphites, must be a low-sul
fur and low-ash material with an isotropic structure. The
structure of filler coke for obtaining reactor graphite is an
important factor. As is known, the central characteristic of
reactor graphite, the radiation-induced transformation rate, is
determined by its structure and properties: coefficient of lin-
ear thermal expansion, anisotropy, degree of crystal structure
perfection, degree of graphitization, density, microstructural
organization — concentration of the spherolitic component.
It is important, that an increase in this concentration delays
the dose-mediated secondary swelling.
Finally, the search for acceptable alternatives has led to
the conclusion that a good candidate, close to KNPS coke in
properties, might be pitch cokes, available from Mechel JSC
(Chelyabinsk Iron and Steel Works, Chelyabinsk) and
NTMK JSC (Nizhny Tagil Iron and Steel Works, Nizhny
Tagil). The two types of pitch coke belong to the isotropic
class, which is seen from the microstructure index (Table 1);
both are low in sulfur and ash.
The data in Table 1 show that pitch coke, when com
pared to KNPS coke, is lower in volatiles (0.7% against 4%)
and lower in true density (2.02 against 2.08 g/cm
were the first two serious problems to be resolved in organiz
ing serial production based on pitch coke.
By traditional technology, to prevent volumetric changes
in the coke during calcination, it must be preliminarily
thermostabilized by heating at 1250°C in a retort furnace.
With a coke low in volatiles and thermally treated for stabili
zation, no excess pressure is produced in the retort furnace,
which allows the ingress of atmospheric air and may initiate
Refractories and Industrial Ceramics Vol. 45, No. 6, 2004
1083-4877/04/4506-0379 © 2004 Springer Science+Business Media, Inc.
Chelyabinsk Electrode Plant Joint-Stock Co., Chelyabinsk, Rus
sia; NIIgrafit Federal State Unitary Enterprise, Moscow, Russia;
Uglerodprom Joint-Stock Co., Moscow, Russia.