Hindawi Publishing Corporation International Journal of Nuclear Energy Volume 2014, Article ID 793908, 7 pages http://dx.doi.org/10.1155/2014/793908
Research Article The Impact of Climate Changes on the Thermal Performance of a Proposed Pressurized Water Reactor: Nuclear-Power Plant Said M. A. Ibrahim,1 Mohamed M. A. Ibrahim,2 and Sami. I. Attia2 1 2
Department of Mechanical Power Engineering, Faculty of Engineering, AL-Azhar University, Nasr City, Cairo 11371, Egypt Nuclear Power Plants Authority, 4 El-Nasr Avenue, P.O. Box 8191, Nasr City, Cairo 11371, Egypt
Correspondence should be addressed to Sami. I. Attia; eng
[email protected] Received 17 February 2014; Accepted 14 March 2014; Published 10 April 2014 Academic Editor: Massimo Zucchetti Copyright ยฉ 2014 Said M. A. Ibrahim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This paper presents a methodology for studying the impact of the cooling water temperature on the thermal performance of a proposed pressurized water reactor nuclear power plant (PWR NPP) through the thermodynamic analysis based on the thermodynamic laws to gain some new aspects into the plant performance. The main findings of this study are that an increase of one degree Celsius in temperature of the coolant extracted from environment is forecasted to decrease by 0.39293 and 0.16% in the power output and the thermal efficiency of the nuclear-power plant considered, respectively.
1. Introduction The main use of water in a thermoelectric power plant is for the cooling system to condense steam and carries away the waste heat as part of a Rankine steam cycle. The total water requirements of the plant depends on a number of factors, including the generation technology, generating capacity, the surrounding environmental and climatic conditions, and the plantโs cooling system, which is the most important factor governing coolant flow rate. Thermal power plants are built for prescribed specific design conditions based on the targeted power demand, metallurgical limits of structural elements, statistical values of environmental conditions, and so forth. At design stage, a cooling medium temperature is chosen for each site considering long term average climate conditions. However, the working conditions deviate from the nominal operating conditions in practice. For this reason, efficiency in electricity production is affected by the deviation of the instantaneous operating temperature of seawater cooling water of a nuclear power plant from the design temperature of the cooling medium extracted from environment to transfer waste heat to the atmosphere via a condenser. Present nuclear plants have about 34โ40% thermal efficiency, depending on site (especially water temperature).
The cooling process in nuclear power plants requires large quantities of cooling water. The huge amounts of water withdrawal and consumption cause that the electricity has to face the impacts of climate change, that is, in form of increasing sea temperatures or water scarcity. For instance, if seas exhibit too high water temperatures, the continued use of water for cooling purposes may be at risk because the cooling effect decreases and also water quality regulations could be violated. An increase in the temperature of cooling water may have impact on the capacity utilization of thermal power plants in two concerns: (1) reduced efficiency: increased environmental temperature reduces thermal efficiency of a thermal power plant, (2) reduced load: for high environmental temperatures, thermal power plantโs operation will be limited by a maximum possible condenser pressure. The operation of plants with river or sea cooling will in addition be limited by a regulated maximum allowable temperature for the return water or by reduced access to water. In the literature, there are few works published to identify these climate change impacts, and few have tried to quantify them. Ganan et al. [1] studied the performance of the pressurized-water reactor- (PWR-) type Almaraz nuclearpower plant and showed that it is strongly affected by the weather conditions having experienced a power limitation
2 due to vacuum losses in condenser during summer. Durmayaz and Sogut [2] presented a theoretical model to study the influence of the cooling water temperature on the thermal efficiency of a conceptual pressurized-water reactor nuclearpower plant. Sanathara et al. [3] gave a parametric analysis of surface condenser for 120 MW thermal power plant and focus on the influence of the cooling water temperature and flow rate on the condenser performance and thus on the specific heat rate of the plant and its thermal efficiency. Daycock et al. [4] measured the actual decrease in efficiencies of gas power plants located in a desert. Linnerud et al. [5] concluded that a rise in temperature may influence the capacity utilization of thermal power plants in two ways. Chuang and Sue [6] studied the performance effects of combined cycle power plant with variable condenser pressure and loading. Costle and Finn [7] reviewed the evaporative cooling technique in temperature maritime climate. In this study, an energy analysis is performed to evaluate the impact of the change in cooling medium temperature on the thermal efficiency of a PWR NPP. The objective is to establish a theoretical methodology to assess the plant performance in different climatic conditions and to emphasize the importance of plant site selection from the environmental temperature point of view. A model for condenser heat balance is developed to determine the functional relationship between the cooling water temperature and the condenser pressure considering that saturation condition exists in the condenser and there is a finite amount of temperature differences between this saturation temperature and the cooling water exit temperature. Employing this condenser heat balance model, a cycle analysis is carried out to determine the heat balance conditions and corresponding power output and thermal efficiency for the prescribed range of cooling water temperatures.
2. Methodology The development of a mathematical model depends upon studying, analysis, and evaluation of the thermal performance and thermodynamics of the secondary cycle of nuclear power plant. This model describes how the impacts of climatic variables and conditions of environment affect the temperature marginal limits of condenser cooling water and the extent of its impacts on the efficiency and performance of the nuclear plant. The thermal and thermodynamic properties, parameters, variables, and mathematical relationships will be formulated to determine the thermal efficiency through the application of the energy and mass conservation laws that govern the mass and heat balance. Figure 1 illustrates a diagram of a proposed PWR nuclear power plant, to address the thermodynamic and heat balance analysis of a PWR NPP. Typical PWR consists of a primary cycle which includes nuclear reactor, steam generator, pressurizer, and reactor coolant pump and the secondary cycle which consists of high-pressure steam turbine (HPST), three low-pressure steam turbines (LPST), moisture separator and reheater (MS/R), deaerator feed water heater, two high-pressure feed water heaters (HPFWH), and three
International Journal of Nuclear Energy low-pressure feed water heaters (LPFWH), condenser, and necessary pumps (feed water pump and condensate pump). A computer program based on the mathematical model representing the secondary circuit of the plant and its components was performed using the engineering equation solver computer program (EES) [8]. The algorithm procedures are performed as follows. (i) Thermodynamic properties (pressure (P), temperature (T), entropy (S), enthalpy (h), and moisture content (X)) at all the inlet and exit of all parts and components of the plant. (ii) Heat balance for each feed water heater and the steam generator. (iii) Output useful work of the turbines and pumps. (iv) Calculation of the amount of heat added to generate steam, as well as the amount of heat rejected from condenser, and calculation of the efficiency of the station. (v) Hence temperature entropy (T-S) diagram of the plant and its components, as well as numerical tabulation of results, being reported. (vi) Determination of the cooling water inlet temperature (๐in ) and exit temperature (๐out ) and the temperature difference. (vii) Assigning the range of change of cooling water temperature ๐cwi during the entire year for the Mediterranean sea as (15โ30โ C). (viii) Computing the impact of the changes of cooling water temperature ๐cwi on the thermal efficiency ๐th and output work ๐net of the plant. (ix) Drawing the relation of ๐cwi versus ๐th and ๐net of the plant. The energy balance equations for the various processes involving steady-flow equipment such as nuclear reactor, turbines, pumps, steam generators, heaters, coolers, reheaters, and condensers in a PWR NPP are as follows. 2.1. Heat Balance Equations (i) The total turbine work, ๐T , kJ/kg, is as follows: ๐T = ๐HPT + ๐LPT ๐HPT = ๐ฬ st (โin โ โout )
(1)
๐LPT = ๐ฬ st (โin โ โout ) , where ๐ฬ st is steam mass flow rate inlet to each turbine, kg/s, โin is enthalpy of steam inlet to each turbine, kJ/kg, โout is enthalpy of steam outlet from each turbine, kJ/kg, ๐HPT is high pressure turbine work, kJ/kg, and ๐LPT is low pressure turbine work, kJ/kg.
International Journal of Nuclear Energy
3
1
2 6
MS
Reheater
8
10
3 S.G
9
HPT
LPT
Hot leg
7 14 Deaerator
Reactor core
5
4
Condenser 11 12
13 15
Cold leg
RCP
23
19 20 21 fwp
22 1HPFWH
2HPFWH
18 3LPFWH
17 4LPFWH
16
cp
5LPFWH
Figure 1: Diagram of PWR nuclear power plant.
(ii) The pumping work, ๐p , kJ/kg, is as follows:
(vi) The cycle efficiency, ๐th , %, is as follows:
๐p = ๐cp + ๐fwp ๐fwp = ๐ฬ fw (โin โ โout )
๐th = (2)
where ๐ฬ fwh is steam mass flow rate inlet to each turbine, kg/s, โin is enthalpy of steam inlet to each Turbine, kJ/kg, โout is enthalpy of steam outlet from each turbine, kJ/kg, ๐fwp is high pressure turbine work, kJ/kg, and ๐cp is low pressure turbine work, kJ/kg. (iii) Heat added to steam generator, ๐add , kJ/kg, is as follows: (3)
where ๐ฬ st is steam mass flow rate exit from steam generator, kg/s, โin is enthalpy of feed water inlet to steam generator, kJ/kg, and โout is enthalpy of steam outlet from steam generator, kJ/kg. (iv) Heat rejected from condenser, ๐Rej , kJ/kg, is as follows: ๐Rej = (๐ฬ mix โ โin โ ๐ฬ mix โ โout ) ,
(4)
where ๐ฬ mix is mixture mass flow rate through condenser, kg/s, โin is enthalpy of mixture inlet to condenser, kJ/kg, and โout is enthalpy of feed water outlet from condenser, kJ/kg.
(i) Closed feed water heaters are as follows: ๐ฬ st โ (โ1 โ โ2 ) = ๐ฬ fw โ (โout โ โin ) ,
(5)
(7)
where ๐ฬ st is steam mass flow rate extracted from turbine to feed water heater, kg/s, ๐ฬ fwh is steam mass flow rate inlet to feed water heater, kg/s, โ1 is enthalpy of steam inlet to feed water heater, kJ/kg, โ2 is enthalpy of steam outlet from feed water heater, kJ/kg, โin is enthalpy of mixture inlet to feed water heater, kJ/kg, and โout is enthalpy of feed water outlet from feed water heater, kJ/kg. (ii) Deaerator is as follows: (๐ฬ st + ๐ฬ fw ) โ โout = (๐ฬ st โ โ1 ) + (๐ฬ fw โ โin ) ,
(8)
where ๐ฬ st is steam mass flow rate extracted from turbine to feed water heater, kg/s ๐ฬ fwh is steam mass flow rate inlet to feed water heater, kg/s, โin is enthalpy of mixture inlet to feed water heater, kJ/kg, and โout is enthalpy of feed water outlet from feed water heater, kJ/kg. 2.3. Heat Balance of Steam Generator. Consider ๐ฬ RCW โ ๐ถRCW โ (๐HL โ ๐CL )
(v) Network done, ๐net , kJ/kg, is as follows: ๐net = ๐๐ โ ๐p .
(6)
2.2. Heat Balance of Feed Water Heaters
๐cp = ๐ฬ fw (โin โ โout ) ,
๐add = ๐ฬ st (โout โ โin ) ,
๐net . ๐add
= (๐ฬ st โ โout ) โ (๐ฬ fw โ โin ) ,
(9)
4
International Journal of Nuclear Energy
where ๐ฬ RCW is reactor coolant water mass flow rate of primary circuit, kg/s, ๐ฬ fw is feed water mass flow rate inlet to steam generator, kg/s, ๐ฬ st is steam mass flow rate outlet from steam generator, kg/s, โin is enthalpy of feed water inlet to steam generator, kJ/kg, โout is enthalpy of steam outlet from steam generator, kJ/kg, ๐HL is temperature of reactor coolant g water at hot leg, โ C, ๐CL is temperature of reactor coolant g water at cold leg, โ C, and ๐ถRCW is specific heat of reactor coolant water of primary circuit, kJ/kgโ
K. 2.4. Heat Balance of Moisture Separator and Reheater. Consider ๐ฬ st โ โin = (๐ฬ st โ โ๐ ) + (๐ฬ fw + ๐ฬ st ) โ โout ,
(10)
where ๐ฬ st is steam mass flow rate inlet to moisture separator and reheater, kg/s, ๐ฬ ๐ is water mass flow rate exit from moisture separator and reheater to feed heater, kg/s โin is enthalpy of feed water inlet to moisture separator and reheater, kJ/kg, โout is enthalpy of steam outlet from moisture separator and reheater, kJ/kg, and โ๐ is enthalpy of steam outlet from moisture separator and reheater, kJ/kg. 2.5. Heat Balance of Cooling Water System (Condenser). The condenser is a large shell and tube type heat exchanger. The steam in the condenser goes under a phase change from vapor to liquid water. External cooling water is pumped through thousands of tubes in the condenser to transport the heat of the condensation of the steam away from the plant. Upon leaving the condenser, the condensate is at a low temperature and pressure. The phase change in turn depends on the transfer of heat to the external cooling water. The rejection of heat to the surrounding by the cooling water is essential to maintain the low pressure in the condenser. The heat is absorbed by the cooling water passing through the condenser tubes. The rise in cooling water temperature and mass flow rate is related to the rejected heat as ๐Rej = (๐ฬ mix โ โin ) โ (๐ฬ fw โ โout ) ๐Rej = ๐ฬ CW โ ๐ถ โ ฮ๐
(11)
ฮ๐ = (๐cwo โ ๐cwi ) , where ๐ฬ CW is cooling water mass flow rate of condenser, kg/s, ๐ฬ fw is feed water mass flow rate of outlet from condenser, kg/s, ๐ฬ mix is mixture mass flow rate of inlet to condenser, kg/s, โ๐ is enthalpy of mixture inlet to condenser, kJ/kg, โout is enthalpy of feed water outlet from condenser, kJ/kg, ๐๐ is condenser saturation temperature, โ C, ๐cwo is temperature of cooling water outlet from condenser, โ C, ๐cwi is temperature of cooling water inlet to condenser, โ C, ฮT is temperature difference between the cooling water exit and inlet temperature, โ C, and ฮ๐hot is temperature difference between the saturation temperature and the cooling water exit temperature, โ C. Modeling assumptions for the secondary cycle are as follows. (i) The thermodynamic conditions of steam at exit of the SG are fixed.
(ii) Thermal power of the PWR changes slowly to provide constant thermodynamic properties of steam at exit of the SG since the variation in cooling water temperature occurs seasonally and very slowly. (iii) The condenser vacuum varies with the temperature of cooling water extracted from environment at fixed mass flow rate into the condenser. (iv) There are constant mass flow rates of condensate and cooling water. (v) There is no pressure drop across the condenser. (vi) The potential and kinetic energies of the flow and heat losses from all equipment and pipes are negligible.
3. Results and Discussions Thermodynamic analysis of the proposed PWR NPP is conducted to investigate the key parameters such as heat added to steam generator, heat rejection, net turbine work, and overall thermal efficiency. Figure 2 illustrates the calculation of the thermodynamic and heat balance analysis of the proposed PWR NPP. Figure 3 showed the thermodynamic and heat balance analysis of the proposed PWR NPP, on the T-S diagram of steam Rankine cycle as obtained from the heat balance of the plant. Table 1 summarizes the calculation of the thermodynamic properties at design conditions satisfying the heat balance for the proposed PWR NPP. Figure 2 and Table 1 are the basis of the parametric study and analysis of the present work. A parametric study is performed to determine the saturation temperature T ๐ถ, corresponding condensate pressure P๐ถ, and also the cooling water exit temperature ๐cwe for the cooling water inlet temperature ๐cwi and condenser terminal temperature difference (T ๐ถ โ ๐cwe ) by using the condenser heat balance model. The results are given in Figures 4 and 5. Figure 4 shows that the relation between ๐cwi and ๐cwe exhibits a proportional linear variation with no effect of the condenser terminal temperature difference (T ๐ถ โ ๐cwe ). The variation of T ๐ถ with ๐cwi also shows a linear dependency having approximately 1โ C difference in T ๐ถ for subsequent condenser terminal temperature difference (T ๐ถ โ๐cwe ) values at any constant value of ๐cwi . Figure 4 depicts the variation between cooling water exit temperature ๐cwe and saturation temperature T ๐ถ in condenser with cooling water inlet temperature ๐cwi . ๐cwi increases, the saturation temperature T ๐ถ increases, and this affect the output work and consequently the efficiency. Figure 5 illustrates variation of the saturation pressure P๐ถ, corresponding to the saturation temperature T ๐ถ, with cooling water inlet temperature ๐cwi . It is seen that an increase in ๐cwi of 1โ C, 5โ C, 10โ C, and 15โ30โ C results is an increase in P๐ถ of 0.00238, 0.01215, 0.02989, and 0.051 bar, respectively. Figure 6 presents the variation of thermal efficiency ๐th with cooling water inlet temperature ๐cwi . When ๐cwi increases by 1โ C, 5โ C, 10โ C, and (15โ30โ C), the thermal efficiency ๐th decreases by 0.16, 0.76, 1.52, and 2.27%, respectively.
International Journal of Nuclear Energy
5 1
2 73.8 289.5 1437 2763
73.8 289.5 0.9975 2763
73.8 289.5 171.1 2763 6
3
9.932 289.5 1008 3028
Moisture separator
1355 2478
LP turbine
HP turbine 9.932 179.6 176 761.5 41.68 252.8 153 2678
S.G
5
73.8 289.5 171.1 1286
7
11 13 13 1.267 106.4 64.21 2689
0.3088 69.78 52.42 2510
14
0.05079 33.16 821.6 2.314
34
73.8 212.2 1608 909.6 2nd HP.F.W.H
1st HP.F.W.H
22
24
21.55 216.2 153 1099
21
Core
R.C. pump
12 12
3.93 199.5 69.45 2859
73.8 289.5 171.1 1286
LP turbine
11
100.7 2583
73.8 248.8 1608 1080
23
LP turbine
9
21.55 216.2
Deaerator
Control rod
4
10
9.932 179.6 1008 2777
9.932 179.6
Pressurizer
Reheater
8
25
F.W. pump
26
21.55 216.2 73.8 181 253.7 926.1 1608 771.1
41.68 252.8 153 1099
2 30 41197 125.8
19
9.932 65.75 1008 276
9.932 102.4 1008 429.7
9.932 139 1008 585.3 3rd LP.F.W.H
18
4th LP.F.W.H
17
27
9.932 179.6 133.7 926.1
9.932 179.6 1184 761.5
28
1.267 106.4 69.45 602.1
3.93 143 69.45 602.1
29
30 1.267 106.4 133.7 446
0.3088 69.75 133.7 446
Condenser 35
5th LP.F.W.H 16
20
36
9.932 33.27 1008 140.2
31
C. pump
15
33
0.05079 33.16 1008 138.9
0.05079 33.16 186.1 292
3 20 41197 84.12
32
0.3088 69.75 186.1 292
Reactor vessel Pressure (bar) Temperature (โ C)
Primary circuit
Flow rate (kg/s) Enthalpy (kJ/kg)
Secondary circuit
Figure 2: Illustration of the EES model equivalent to the proposed PWR NPP thermodynamic and heat balance analysis.
0.11
400 350
32 31 20 19 22 21 18 17 23 16
250 200 150 100 50
12 11
1
41.68 bar
2
21.55 bar
3
9.932 bar
4
24 15
3.93 bar
26 14 25 28 27 13 29
1.267 bar
0 0
73.8 bar
1
6
0.08 5 7 8
0.2
2
0.4
3
10 0.6
4 5 S (kJ/kgยทK)
0.05
0.8
6
7
0.07 0.06
9
0.3088 bar 0.05079 bar
0.09
Pc (bar)
T (โ C)
0.1
30
300
8
9
0.04 0.03
Figure 3: T-S diagram of the proposed PWR nuclear power plant thermodynamic and heat balance analysis.
15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Tcwi (โ C) TTD = 3โ C TTD = 4โ C TTD = 5โ C
Figure 5: Variation of saturation pressure P๐ถ , corresponding to the saturation temperature T ๐ถ , with cooling water inlet temperature ๐cwi .
50
Tcwe , Tc (โ C)
45 40 35 30 25 20 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Tcwi (โ C) Tcwe TTD = 3โ C
TTD = 4โ C TTD = 5โ C
Figure 4: Variations of cooling water exit temperature ๐cwe and saturation temperature T ๐ถ with cooling water inlet temperature ๐cwi .
Figure 7 gives the variation of net power output ๐ฬ net with cooling water inlet temperature ๐cwi . An increase in ๐cwi of 1โ C, 5โ C, 10โ C, and 10โ35โ C corresponds to decrease in ๐ฬ net by 0.39293, 2.166, 4.3683, and 6.547%, respectively. The change of condenser conditions, that is, ๐C and P๐ถ, with ๐cwi results in a decrease of 6.547% in output power of the plant ๐คฬ net for the ๐cwi range of 15โ30โ C as shown in Figure 7. It is observed from Figure 6 that an increase from 15 to 30โ C in the temperature of the coolant extracted from environment results in a decrease from 37.57 to 35.3% in the thermal efficiency of the NPP.
4. Conclusions A condenser heat balance model is developed to determine the functional relationship between the cooling water temperature and the condenser pressure. Thus, a cycle analysis
6
International Journal of Nuclear Energy Table 1: Thermodynamic data for the proposed pressurized water reactor nuclear power plant. Temperature, ๐ (โ C)
Pressure, ๐ (bar)
Enthalpy, โ (kg/kj)
Entropy, ๐ (kj/kgโ
k)
Quality, ๐ฅ
1
289.5
73.8
2763
5.779
0.9975
2
289.5
73.8
2763
5.779
0.9975
171.1
Station number
Mass flow rate, ๐ฬ (kg/s) 1608
3
289.5
73.8
2763
5.779
0.9975
1437
4
252.8
41.68
2678
5.82
0.9283
153
5
216.2
21.55
2583
5.868
0.8841
100.7
6
179.6
9.932
2478
5.926
0.8513
1355
7
179.6
9.932
761.5
2.136
0
176
8
179.6
9.932
2777
6.588
1
1008
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
289.5 289.5 199.5 106.4 69.78 33.16 33.16 33.27 65.75 102.4 139 179.6 181 212.2 248.8 252.8 216.2 216.2 179.6 143 106.4 106.4 69.75 69.75 33.16 252.8 20 30
73.8 9.932 3.93 1.267 0.3088 0.05079 0.05079 9.932 9.932 9.932 9.932 9.932 73.8 73.8 73.8 41.68 21.55 21.55 9.932 3.93 1.267 1.267 0.3088 0.3088 0.05079 41.68 3 2
1286 3028 2859 2689 2510 2314 138.9 140.2 276 429.7 585.3 761.5 771.1 909.6 1080 1099 1099 926.1 926.1 602.1 602.1 446 446 292 292 1286 84.12 125.8
3.154 7.085 7.177 7.288 7.419 7.579 0.4799 0.481 0.9022 1.333 1.728 2.136 2.141 2.436 2.774 2.819 2.836 2.483 2.499 1.77 1.79 1.378 1.401 0.9519 0.9796 3.174 0.2961 0.4365
0 Superheated Superheated Superheated 0.9503 0.8978 0 Sub. liquid Sub. liquid Sub. liquid Sub. liquid 0 Sub. liquid Sub. liquid Sub. liquid 0 0.09234 0 0.08166 0 0.0697 0 0.06599 0 0.06319 0.11 Sub. liquid Sub. liquid
171.1 1008 69.45 64.21 52.42 821.6 1008 1008 1008 1008 1008 1184 1608 1608 1608 153 153 253.7 133.7 69.45 69.45 133.7 133.7 186.1 186.1 171.1 41197 41197
for the proposed NPP is carried out to determine the heat balance conditions originating from temperature change of cooling medium. It can be concluded that the output power and the thermal efficiency of the plant decrease by approximately 0.3929 and 0.16%, respectively, for 1โ C increase in temperature of the condenser cooling water extracted from the environment. The impact of climate changes in condenser cooling water is an important design consideration when constructing
PWR NPP. A reduction in production capacity due to an increase in environment temperature would represent a drop of production that might need to be replaced somewhere. The effect of climatic changes shows to be important in the design of more effective cooling technique and to device methods to compensate for the loss in plant output and system capacity. Climate considerations will also become even more important when deciding where to build new thermal power plants.
International Journal of Nuclear Energy
1.05E + 06
cp: CW: cwi: CL: cwo: fw: fwp: HL: HPT: LPT: in: mix: out: p: RCW: Rej: T: .: HP: LP: NPP: PWR: RC: SG:
1.03E + 06
Conflict of Interests
1.00E + 06
The author declares that there is no conflict of interests regarding the publication of this paper.
9.75E + 05
References
38 37.5
๐th (%)
37 36.5 36 35.5 35 34.5 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Tcwi (โ C) TTD = 3โ C TTD = 4โ C TTD = 5โ C
Figure 6: Variation of thermal efficiency ๐th with cooling water inlet temperature ๐cwi .
Wฬ net (watt)
7
9.50E + 05 9.25E + 05
15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Tcwi (โ C) TTD = 3โ C TTD = 4โ C TTD = 5โ C
Figure 7: Variation of net power output ๐ฬ net with cooling water inlet temperature ๐cwi .
Nomenclature C: h: ๐:ฬ p: ๐:ฬ T: TTD: ๐ฬ net : ๐: add: c:
Specific heat (kJ/kgโ
K) Enthalpy (kJ/kg) Mass flow rate (kg/s) Pressure (bar) Net rate of heat transferred (kW) Temperature (K) Terminal temperature difference Net rate of work (kW) Efficiency (%) Added Condenser
Condensate pump Cooling water Cooling water inlet Cold leg Cooling water outlet Feed water Feed water pump Hot leg High pressure turbine Low pressure turbine Inlet Mixture Outlet Pump Reactor cooling water Rejection Turbine Per unit time High pressure Low pressure Nuclear power plant Pressurized water reactor Reactor coolant Steam generator.
[1] J. Gaหnaยดn, A. R. Al-Kassir, J. F. Gonzยดalez, A. MacIยดฤฑas, and M. A. Diaz, โInfluence of the cooling circulation water on the efficiency of a thermonuclear plant,โ Applied Thermal Engineering, vol. 25, no. 4, pp. 485โ494, 2005. [2] A. Durmayaz and O. S. Sogut, โInfluence of cooling water temperature on the efficiency of a pressurized-water reactor nuclear-power plant,โ International Journal of Energy Research, vol. 30, no. 10, pp. 799โ810, 2006. [3] V. Milan Sanathara, P. Ritesh Oza, and S. Rakesh Gupta, โParametric analysis of surface condenser for 120 MW thermal power plant,โ International Journal of Engineering Research & Technology, vol. 2, no. 3, 2013. [4] C. Daycock, R. Jardins, and S. Fennel, โGeneration cost forecasting using on-line thermodynamic models,โ in Proceedings of the Electric Power, Baltimore, Md, USA, March 2004. [5] K. Linnerud, T. K. Mideksa, and G. S. Eskeland, โThe impact of climate change on nuclear power supply,โ Energy Journal, vol. 32, no. 1, pp. 149โ168, 2011. [6] C.-C. Chuang and D.-C. Sue, โPerformance effects of combined cycle power plant with variable condenser pressure and loading,โ Energy, vol. 30, no. 10, pp. 1793โ1801, 2005. [7] B. Costle and D. P. Finn, Reviewed the Evaporative Cooling Technique in Temperature Maritime Climate, 2005. [8] http://www.fchart.com/.
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