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ISSN 00406015, Thermal Engineering, 2015, Vol. 62, No. 5, pp. 322–328. © Pleiades Publishing, Inc., 2015.
Original Russian Text © V.F. Kasilov, A.A. Dudolin, I.V. Gospodchenkov, 2015, published in Teploenergetika.
The Effectiveness of Using the CombinedCycle Technology
in a Nuclear Power Plant Unit Equipped with an SVBR100 Reactor
V. F. Kasilov, A. A. Dudolin, and I. V. Gospodchenkov
Moscow Power Engineering Institute National Research University, Krasnokazarmennaya ul. 14, Moscow, 111250 Russia
email: kasilovvf@mpei.ru
Abstract—The design of a modular SVBR100 reactor with a leadbismuth alloy liquidmetal coolant is
described. The basic thermal circuit of a power unit built around the SVBR100 reactor is presented together
with the results of its calculation. The gross electrical efficiency of the turbine unit driven by saturated steam at
a pressure of 6.7 MPa is estimated at ηel
= 35.5%. Ways for improving the efficiency of this power unit and
increasing its power output by applying gasturbine and combinedcycle technologies are considered. With
implementing a combinedcycle powergenerating system comprising two GE6101FA gasturbine units with a
total capacity of 140 MW, it becomes possible to obtain the efficiency of the combinedcycle plant equipped with
the SVBR100 reactor ηel
= 45.39% and its electrical power output equal to 328 MW. The heatrecovery boiler
used as part of this power installation generates superheated steam with a temperature of 560°C, due to which
there is no need to use a moisture separator/steam reheater in the turbine unit thermal circuit.
Keywords: nuclear power plant unit, SVBR100 nuclear reactor, gasturbine unit, combinedcycle power
plant, steam turbine, turbine unit thermal circuit, power unit efficiency and capacity
DOI: 10.1134/S0040601515050043
Works are presently underway in structural units of
the Rosatom State Atomic Energy Corporation on
developing an experimental industrial NPP power unit
equipped with an SVBR100 nuclear reactor (the
Dimitrovgrad town in the Ul’anovsk oblast) with ther
mal capacity Qr = 280 MW and a steamturbine unit
with electrical capacity Nel = 100 MW. The SVBR100
modular fastneutron reactor [1, 2] has been designed
to operate in a closed fuel cycle with an eutectic lead–
bismuth alloy serving as a liquid metal coolant. This
technology has been elaborated during operation of
similar reactors at Russian nuclear submarines, and
the project of the SVBR100 reactor meets to a con
siderable degree the requirements posed on modern
nuclear power installations, specifically, the safety
requirements, the requirements for the reactor plant
service life (from 40 to 60 years), and for achieving the
level of specific capital outlays for constructing a
nuclear power unit commensurable with those for
thermal power plants $(1000–1700)/kW. Small
capacity power units may be attractive for projects with
a limited amount of investments, and owing to a high
safety level, NPPs equipped with SVBR100 reactors
can be constructed in close vicinity of residential
areas. Owing to these features, such power units can be
used for district heating purposes in cities [3, 4].
According to assessments made by the International
Atomic Energy Agency (IAEA), the demand for
small and mediumcapacity reactors (100–400 MW)
around the world to the year 2040 will make from 500
to 1000 units, and the total cost of this market will
make $(300–600) billion. Russia, the United States,
France, and China occupy the leading positions in
research and development works on these reactors. It
should be noted that SVBR100 reactors may account
for 10–15% in the new segment of the nuclear power
industry market.
An important feature of the SVBR100 reactor
plant is that its primary coolant circuit has an integral
layout; the equipment of this circuit is placed in the
strong casing of the reactor monounit (RMU), and the
hydraulic links are formed without using pipelines and
valves (Fig. 1).
The RMU central part contains an assembly com
prising the core and the reactor control and protection
system’s (CPS) control rods. The core is surrounded
by an invessel radiation shield, which accommodates
evaporator modules and reactor coolant pumps
(RCPs). The RMU heat removal loops operate with
natural circulation of coolants the intensity of which is
sufficient for passively cooling down the reactor with
out dangerous overheating of its core. A protective
plug is mounted above the core, on the head of which
the drives of CPS absorber rods are mounted. Owing
to its compact overall dimensions (4.53 m in diameter
and 7.55 m in height), the reactor monounit can be
transported in completely prefabricated state (also by
railway), due to which NPPs equipped with such reac
tors can be constructed within a shorter period of time
and at a lower cost. The time interval between the
reactor refueling operations is 7–8 years. The adopted
circulation arrangement with free levels of coolant in
the RMU upper part and in the channels of steam gen
erator modules taken in combination with a low cool
ant flow velocity in the path downtake parts ensure
reliable separation of steam–water mixture from the
coolant if loss of tightness occurs in the evaporator
module tube system. The secondary coolant circuit
operates according to the scheme with multiple forced
circulation of steam–water working medium.
Owing to the reactor, steam generator modules,
reactor coolant pumps, and other equipment being
placed in a common casing that does not contain any
pipelines or valves, a high level of reactor plant safety
is ensured. For example, the possibility of the follow
ing emergency situations is excluded: instantaneous
neutron reactor power excursion, loss of coolant from
the reactor, and propagation of radioactivity from the
reactor coolant system on a scale at which the popula
tion living outside of the NPP boundaries have to be
evacuated. The safety systems used as part of the reac
tor plant come in action in a passive manner and do
not contain elements failures of which may be con
nected with the influence of a human factor. The reac
tor plant safety does not depend on the state of steam
turbine unit systems and equipment, which is designed
and manufactured according to the generalindustry
codes and regulations.
This article presents the version of an SVBR100
reactorbased condensing power unit’s thermal circuit
without steam superheating modules comprising a
K1006.7 twocylinder turbine (Fig. 2) that has been
prepared by the authors of this article and calculated
using the Thermoflow software system.
The turbine highpressure cylinder’s (HPC) flow
path is fitted with a throttle steam admission system
and a looptype steam expansion arrangement. The
twoflow lowpressure cylinder (LPC) used in the
considered version has laststage rotor blades with
length l2 = 665 mm. In case of using 960mm or longer
rotor blades it is possible to implement a singleflow
steam expansion arrangement in the LPC. The tur
bine unit regenerative system consists of two high
pressure heaters, a deaerator operating at pressure
pd = 0.86 MPa, three lowpressure heaters, the main
ejector, and a gland steam ejector. The steam flow rate
from the reactor’s steam generator at the feed water
temperature tf.w = 226°C is equal to 160.86 kg/s. The
saturated steam pressure upstream of the turbine HPC
is р0 = 6.7 MPa. Such a turbine unit version with a rea
sonable level of vacuum in the condenser (in the pre
sented calculation version, pc = 6 kPa) can be imple
mented only with subjecting steam to moisture separa
tion and reheating. In this connection, a moisture
separator/steam reheater (MSR) with the split pres
sure pspl = 0.99 MPa is installed downstream of the
steam turbine HPC. The MSR steam reheating part’s
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Fig. 1. Longitudinal section of the SVBR100 reactor
monounit. (1) Reactor core, (2) RMU casing, (3) protective
plug, (4) evaporator modules, (5) CPS drives, and (6) RCP.
first stage receives steam from the turbine HPC extrac
tion, and its second stage receives live steam from the
turbine unit main steam line (see Fig. 2).
The presented power unit has electric capacity
N el = 101.33 MW, the turbine unit electrical efficiency
is ηelgr = 35.5%, the heat rate is q elgr = 9947 kJ/(kW h),
and the specific nuclear fuel rate is bn.f = 158 g/MW.
Unfortunately, like for the technologies of water
cooled watermoderated powergenerating reactors
(VVER), owing to the fact that the live steam temper
ature in the steamturbine unit equipped with an
SVBR100 reactor is limited at the level corresponding
to saturation state (t0 = 282.8°C), the maximum
achievable gross efficiency cannot be higher than 37%.
The relatively low level of efficiency and the problems
that arise during wet steam expansion in the turbine
flow path prompt the designers to find solutions that
would make it possible to achieve better performance
efficiency of the steam turbine unit and higher reliabil
ity of the nuclear power unit at the existing stateof
theart in power engineering. Application of gastur
1.895 764.1
22.5 180.1
11.8 217.2
0.86 734.3
149.1 173.4
1.952 2689.8
3.497 931.1
149.1 207.97
7.58 890.6
18.3 245
3.654 2768.1
154.75 282.8
6.54 112.5
1.016 452.1
0.426 472.2
3.619 1059
6.11 286.3
0.1445 323.91
96.9 72.35
1.171 303.8
0.1516 2693.7
68.67 244.5
0.9885 2610.3
88.7 37.25
1.326 157.2
5.56 75.74
0.0398 2635.9
0.95 2989.7
87.6 36.7
0.006 2556.7
98.9 MW
p, MPa h, kJ/kg
G, kg/s t, °C
Fig. 2. Thermal process circuit of the power unit built around the SVBR100 reactor. R is the reactor; HIPC is the steam turbine’s combined high and intermediatepressure
cylinder; S is the MSR separator section; SR1 and SR2 are the MSR’s steam reheating sections 1 and 2, respectively; LPC is the steam turbine’s lowpressure cylinder; C is the
condenser; CP is the condensate pump; LPH1–LPH3 are the lowpressure heaters; D is the deaerator; FWP is the feed water pump; HPH4–HPH5 are the highpressure
heaters; and EC are the ejector coolers.
149.1 223.4
160.86 226
6.97 179.4
0.86 603.3
6.932 2777.9
6.11 285.2
160.86 287
7.74 244.5
6.932 1263.6
3.619 2702.8
6.54 192.8
0.4473 2843.3
KASILOV et al.
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bine and combinedcycle technologies in NPP power
units is the most significant solution [5–8]. In our opin
ion, those who strive to achieve the efficiency of the
abovementioned power units higher than 45% should
pay keen attention to the possibility of using combined
cycle technologies in nuclear power engineering.
The most accessible and simple approach to solv
ing the problems concerned with maneuverability,
covering the peak loads of electricity consumers, and
supplying heat to them is to use gas turbine units
(GTUs). Since GTUs feature high load pickup rate
capabilities and short startup time, they can serve as
sources of reliable emergency and standby power sup
ply to the auxiliaries of NPP power units. It is possible
to consider application of an independent GTU with a
heat exchanger instead of a boiler unit (the latter usu
ally operates on fuel oil), which is designed at all NPPs
for supporting the adjustment and commissioning
works. The time taken to install a GTU is shorter as
compared with that taken to construct an NPP power
unit; therefore, it can generate electricity already in
the course of constructing and installing the main
equipment. The GTU can also be used as a peaking
duty power unit for generating electricity and for
replacing the means for preheating feed water in the
NPP turbine unit regenerative system. We mean here
the power unit maneuvering power generated both by
the peakingduty GTU and by forcing the steam tur
bine with fully or partially disconnecting the regener
ative steam extractions. Different arrangements for
replacing steam extractions to the MSR can also be
considered. It should be pointed out that the GTU
power performance characteristic allows its electric
power output to be increased by 20–30% in the coldest
periods of operation (the peaks of electric and heat
loads in fall and winter). Since GTUs have the highest
maneuverability indicators, their application is of
much importance not only in covering peak loads, but
also in extending the adjustment range of the NPP tur
bine unit, and it is primarily connected with increasing
the upper power output limit of the existing power
unit. We cannot but point out the possibility of inde
pendent GTU operation during scheduled and off
scheduled outages of the nuclear reactor.
The majority of the abovementioned GTU capaci
ties are connected with using the “nuclear power unit +
GTU” process circuits, which do not allow a consider
able growth of power unit efficiency to be obtained, also
due to a low extent of binarity in their thermodynamic
cycles. As is well known, the highest efficiency in ther
mal power engineering (50–60%) is obtained by using
combinedcycle power plants (CCPs). The use of com
binedcycle technology at NPPs opens the possibility to
obtain steam with a temperature of higher than 500°C
in the heatrecovery boiler, due to which there will be no
need to use an expensive MSR, and the turbine can be
designed for the superheated steam expansion condi
tions. The use of such solutions will make it possible to
achieve considerable improvement not only in the
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power unit efficiency, but also in the reliability of its
main equipment. It should also be borne in mind that
the steam rate per unit of generated power in wetsteam
turbines of NPPs is significantly higher than it is in the
turbines of thermal power plants operating on super
heated steam. For example, for superheating live steam
supplied to a 1000 MW turbine unit to a temperature of
540°C, up to 35% of additional power capacity is
required in the reactor evaporation modules, which
corresponds to the required GTU capacity equal to
around 1500 MW. The version involving the use of
GTU of a smaller capacity, e.g., 300 MW, will make it
possible to obtain live steam superheating by only 30–
40°C and achieve gross efficiency equal to around 39%.
Below, the data reported in [5, 8] are given as exam
ples of using different process circuits of combined
cycle power units at NPPs. In [5], the effectiveness of
using the GTE130850 gas turbine unit jointly with a
VVER1000 reactor and a K10005.9 steam turbine
was considered. Versions involving live steam super
heating, reheating, and partial heating of feed water
were calculated. It was shown that the system involving
steam reheating in the CCP heatrecovery boiler is the
most efficient one. In [8], the results obtained from cal
culations of a CCP comprising the AP600 nuclear reac
tor designed by Westinghouse (a 600MW lightwater
reactor), a 1151.5 MW threecylinder steam turbine
unit, and four V94.3A gas turbine units with the total
capacity equal to 972.5 MW were presented. As a result,
the capacity of such CCP totaled Nel = 2124 MW.
Owing to the use of heat contained in the flue gases
exhausted from the GTUs, the steam produced by the
AP600 reactor’s steam generator is superheated in the
steam superheating sections of four heatrecovery boil
ers (HRBs) placed downstream of it is superheated to a
level at which the live steam temperature upstream of
the turbine is raised to t0 = 530°C. Feed water upstream
of the steam generator is heated in the HRB econo
mizer sections to a temperature of 226.9°C, and then
saturated steam is generated in the reactor plant at a
pressure of 5.72 MPa. One lowpressure heater, a
deaerator, and a highpressure heater are used in the
steam turbine unit thermal process circuit for heating
feed water downstream of the condenser. It has been
found from the calculation results that the use of com
binedcycle technology results, apart from obtaining a
significantly increased power output, the growth of
power unit efficiency from 33.0% in the initial version to
49.4% in the CCP version.
Clearly, the CCP process circuit presented above is
difficult to implement, and primarily in case of using
highcapacity reactor plants operating with large
steam flow rates. However, for NPPs equipped with
small and mediumcapacity reactors such solutions
can well be implemented and will make it possible to
obtain significant gains in efficiency, power capacity,
and maneuverability. The authors of this article calcu
lated a few versions of thermal process circuits for a
CCP equipped with a SVBR100 reactor. One of these
KASILOV et al.
GE 6101FA
70.2 MW
70.2 MW
GTU no. 1
GE 6101FA
GTU no. 2
160.9 560
0.1018 629.4
412.5 594.4
187.6 MW
0.006 2333.1
140.1 36.16
7.14 2770.7
160.9 287.2
0.006 151.5
7.85 972.2
140.1 36.16
160.9 226
8.01 479.4
1.013 125.2
160.9 112.9
412.5 143.5
p, MPa h, kJ/kg
G, kg/s t, °C
Fig. 3. Thermal process circuit of the PGU330YaR combinedcycle power plant comprising the SVBR100 nuclear reactor.
HRB is the heatrecovery boiler, SSS is the steam superheating section, and ES is the economizer section. The other notation is
the same as in Fig. 2.
versions with the feed water temperature upstream of
the reactor plant tf.w = 226°C is shown in Fig. 3. This
thermal circuit includes a lowpressure heater and a
deaerator. Prior to be fed to the reactor plant, feed
water is heated in the HRB economizer section. Mass
flow rates (G, kg/s) and the thermodynamic parameters
of working media (pressure р, MPa; temperature t, °C;
and enthalpy h, kJ/kg) are indicated at the thermal cir
cuit characteristic points. The process circuit does not
show auxiliary pipeline mains, e.g., for steam from the
turbine end seals and from the control valve stems.
However, the relevant flow rates of steam and water
were taken into account in calculating the circuit,
which was modeled to a sufficient detail. The power
unit output and the level of its electrical efficiency
were estimated in the calculations.
We consider the power unit configuration compris
ing two GE 6101FA gas turbine units each having a
capacity of 70 MW, which are supposed to be assembled
and tested at the Russian Gas Turbines Company’s pro
duction plant established within the framework of a
joint enterprise of the General Electric Concern, the
INTER RAO UES Company, and the Rostekh State
Corporation, which is presently under construction.
The total flow rate of gases with a temperature of 595°С
supplied from the GTUs to the heatrecovery boiler is
412.5 kg/s. The heatrecovery boiler’s steam superheat
ing section (see Fig. 3) is able to produce superheated
steam with a temperature of 560°С at a pressure of
7.0 MPa (the live steam pressure upstream of the tur
bine р0 = 6.7 MPa). The steam turbine set power output
at the outdoor air temperature to.a = 15°C was found to
be Nel = 187.6 MW (the steam turbine is marked as
K1906.7). As a result, the total capacity of the CCP
(marked as PGU330YaR) is Nel = 328.1 MW. At these
operating parameters, the gross electrical efficiency was
found to be ηelgr = 45.39%. The twocylinder steam tur
bine consists of a combined high and intermediate
pressure cylinder and a lowpressure cylinder with the
960mmlong laststage rotor blade. The steam expan
sion process in the turbine flow path is shown in Fig. 4.
The table presents the PGU330YaR power out
put and efficiency values depending on the power out
put ratio of GTU 1 and GTU 2. Here, we speak about
the CCP indicators with the GTUs operating at partial
loads up to the mode in which one of them (GTU 1)
operates at 50% of its rated power output and the sec
ond one (GTU 2) is shut down. Under such condi
tions, the PGU330YaR total electric power output
varies from 328.1 to 177.6 MW and its efficiency, from
45.39 to 35.5%.
The results from calculations of the PGU330YaR
carried out for different operating modes of the
GE 6101FA gas turbine units depending on the out
door air temperature are presented in Fig. 5. In the
range of to.a from –30 to 30°C the power output varies
by approximately 45 MW.
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p = 7 MPa
–10 –3.2
to.a, °С
p = 1 MPa
Fig. 5. Electric power output of the PGU330YaR com
binedcycle plant as a function of outdoor air temperature.
h, kJ/kg
p = 152 kPa
x = 0.903
p = 43 kPa
p = 6 kPa
S, kJ/(kg K)
Fig. 4. Steam expansion process in the K1906.7 turbine
flow path.
The authors of this article carried out calculations of
the CCP thermal circuit shown in Fig. 3 with the feed
water temperature upstream of the SVBR100 reactor
(after the HRB economizer section) tf.w = 240°C. To do
so, we had to use GE 6111FA GTUs with a capacity of
72 MW [their efficiency is equal to 34.97% subject to
fulfilling the requirements specified in GOST (State
Standard) R 522002004)]. As a result, the CCP total
capacity was Nel = 339.1 MW and its gross efficiency
ηelgr = 46.23%.
It should be pointed out that certain limitations are
imposed on implementing CCPs and GTUs in the
NPP process circuit in regard of fire safety, the regula
tions for which will need the relevant correction. Lim
itations may also be encountered in substantiating the
economic efficiency of NPP power unit projects with
the use of combinedcycle technology, for example,
due to a high discounting rate adopted in the nuclear
power industry, problems connected with determining
the tariffs for electricity, and dispatch control con
straints in operating the power units. At the same time,
the authors of this article are sure that the necessary
possibilities and scientific background for using com
binedcycle technologies in nuclear power engineer
ing are available in Russia already at present. In con
trast to the Russian thermal power industry, in which
we did not become the leaders in implementing com
binedcycle technologies, the nuclear power industry
of Russia can occupy the leading positions among the
developed countries of the world community.
(1) The calculation results presented in this work
have demonstrated that the use of combinedcycle
technology in the power unit equipped with an
SVBR100 nuclear reactor allows the electric power
output of around 330 MW with efficiency at the level
of 45% to be obtained.
(2) In our opinion, the nuclear power industry of
Russia can and should become one of leaders in
implementing combinedcycle technologies in the
process circuits of power units equipped with small
and mediumcapacity nuclear reactors.
The power output and efficiency values of the PGU330YaR power installation depending on the capacities of GE 6101FA
gasturbine units at to.a = 15°C (subject to the conditions specified in GOST (State Standard) R 522002004)
Shares of gas turbine units in generating the power output
(NGTU1/NGTU2, %/%)
Ratio of gas turbine unit power outputs
Ratio of gas turbine unit efficiencies
ηGTU1/ηGTU2, %/%
Steam turbine unit electric power output,
CCP power output NCCP, MW
CCP efficiency ηCCP, %
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KASILOV et al.
1. A. V. Zrodnikov, G. I. Toshinskii, and V. S. Stepanov,
“Conversion of the technology of lead–bismuthcooled
reactors: from the reactors for nuclearpowered subma
rines to powergenerating reactors and ways of making
nuclear power engineering on the basis of fastneutron
reactors more attractive for investors,” in Proceeding of
the International IAEA Conference “Fifty Years of Nuclear
Power – the Next Fifty Years,” Obninsk, 2004.
2. A. V. Zrodnikov, G. I. Toshinskii, O. G. Grigor’ev,
Yu. G. Dragunov, V. S. Stepanov, N. N. Klimov,
I. I. Kopytov, V. N. Krushel’nitskii, and A. A. Gruda
kov, “Modular multipurpose lead–bismuth fast reac
tors for nuclear power engineering,” Therm. Eng.
52 (1), 17 (2005).
3. Yu. N. Kuznetsov, L. S. Khrilev, and V. P. Brailov, “The
technical and economic principles and lines of develop
ment of nuclear district heating cogeneration,” Therm.
Eng. 55 (11), 926 (2008).
4. A. S. Kurskii and V. V. Kalygin, “The effectiveness of
nuclear district heating cogeneration,” Energ. Polit.,
No. 4, 48–57 (2013).
5. S. V. Tsanev and S. N. Belozerov, “On the use of com
binedcycle process circuits for steam turbine units
operating on saturated steam,” Izv. Vyssh. Uchebn.
Zaved., Energetika, No. 12, 70–74 (1988).
6. Z. Yu. Novikova, Achieving Better System Efficiency of
PowerGenerating Complexes on the Basis of Nuclear
Power Plants and Gas Turbine Units with Heat Storage,
Candidate’s Dissertation in Technical Sciences (Sara
tov Gos. Tekhn. Univ, Saratov, 2013).
7. Z. Yu. Novikova and V. A. Khrustalev, “The effectiveness
of refusing from highpressure heaters in the NPPbased
combinedcycle power plant’s process circuit,” Izv.
Vyssh. Uchebn. Zaved., Probl. Energ., No. 9, 69–77
8. M. A. Darwish, F. M. Al Awadhi, and A. O. Bin Amer,
“Combining the nuclear power plant steam cycle with
gas turbines,” Energy, No. 35, 4562–4571 (2010).
Translated by V. Filatov
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