Influence of Extraction Steam Pressure Loss on Exergy Economy of PWR Nuclear Power Plant Shenglong Wang 1,a,Junpeng Li 1,b,Jun Ma 2,c

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1 International Power, Electronics and Materials Engineering Conerence (IPEMEC 2015) Inluence o Extraction Steam Pressure Loss on Exergy Economy o PWR Nuclear Power Plant Shenglong Wang 1,a,Junpeng Li 1,b,Jun Ma 2,c 1 College o Energy and Power Engineering,Northeast Dianli University,Jilin ,Jilin Province,China 2 Tianjin huaneng yangliuqing power co.,ltd,tianjin ,China a wang-sl@oxmail.com, b @qq.com, c @qq.com Keyword: PWR nuclear power plant ; Coupling characteristics ; Extraction steam pressure loss ; Energy loss ; Energy eiciency Abstract. Reheat system o PWR nuclear power unit in use o steam reheat method.heat recovery system and reheat steam system o PWR nuclear power units th strong coupling, so the impact o changes in heat recovery steam extraction pressure loss o nuclear power plants is more complex than thermal power.accorng to the characteristics o the secondary circuit o PWR nuclear power plant, the exergy loss stribution matrix and steam-water stribution matrix o the reheat and heat recovery system has been listed. Based on the small sturbance analysis method, taking a 1000MW nuclear power plant thermal system as an example, when the heat recovery extraction steam pressure loss o a heater decreased by 5%, the variation o exergy loss and extraction coeicient o heat recovery and reheat system is quantitatively calculated. Introduction When the steam rom the extraction steam mouth o cylinder long to the heater,the reasons such as throttle o vavle and riction o pipe ll cause the pressure loss o the extraction steam. Due to the pressure loss o heat recovery extraction steam,the ability to work o steam and the economy o the PWR nuclear power unit ll decline.extraction steam pressure loss is a subtle thermal power loss,but it ll lead to decrease in working capacity o steam and thermal economy o a power plant[1,2]. Some scholars have analyzed the inluence o extraction steam pressure loss on exergy eiciency o thermal power unit. The inluence o changes o extraction steam pressure loss on PWR nuclear power unit is more complex than thermal power unit because o the coupling o heat recovery system and reheat system o PWR nuclear power unit. Through the quantitative calculation o 1000 mw PWR nuclear power unit[3],we have analyzed that t Inluence o extraction steam pressure Loss on exergy economy o PWR nuclear power unit. Inluence o Extraction Steam Pressure Loss on the parameters o the heater Accorng to the relevant literature we know that, when the extraction pressure loss o No.i heater changing,i the heater No.i th a drain cooler,the hydrophobic temperature ll remain constant;i not, the hydrophobic temperature ll be changed.for the heater No.i+1,i the heater th a drain cooler, the hydrophobic temperature ll be changed;i not,the hydrophobic temperature ll remain constant[4]. The variation o hydrophobic temperature and eed water temperature are the same.when the extraction pressureloss o No.i heater changing, we can use hydrophobic temperature and eed water temperature o No.i heater as the independent variable,so we can compute the change o the unit economy. The calculation model o heater is shown in igure The authors - Published by Atlantis Press 507

secondary circuit between PWR nuclear power unit and thermal power unit. High parameters steam o reheat system come rom new steam and extraction steam o high pressure cylinder.

2 (a) Have hydrophobic cooler (b) No hydrophobic cooler Figure.1 calculation model o the heater Quantitative Calculation o 1000MW nuclear power unit Reheat system o PWR nuclear power unit in use o steam-steam reheat is the main erence o thermal system o secondary circuit between PWR nuclear power unit and thermal power unit. High parameters steam o reheat system come rom new steam and extraction steam o high pressure cylinder.drain o moisture separator reheater long to deaerator and high pressure heater. Quantitative Calculation o PWR nuclear power unit is complex because o the coupling o heat recovey system and reheat system. As shown in Figure.2,the No. 1, No. 2, No. 3, No. 4 heater is low pressure heater. The No.5 heater is deaerator. The No.6 and No.7 heater is high pressure heaters. The No.8 and No.9 heater is reheaters.the No.10 is separator.the exhaust steam o high pressure cylinder what long to moisture separator reheater is separated into saturated steam and water.drain rom the separator long to deaerator,and saturated steam rom the separator long to reheater No.8 and No.9. Ater reheated,the micro superheated steam what long into the low pressure cylinder ll continue to go to work. Steam heating source o reheater No.8 and No.9 come rom new steam and extraction steam o high pressure cylinder,and drain rom the reheater long to the high pressure heater No.7. Because o the coupling o heat recovery system and reheat system,when extraction steam pressure loss changing, the steam-water stribution and exergy loss stribution o both heat recovery system and reheat system also change. 508

3 Figure.2 Thermal system o 1000MW PWR nuclear power unit Steam-water stribution matrix o secondary-circuit thermal system.the steam-water stribution matrix expression o secondary circuit is [5,6]: Aα + A α + Aα + q = b (1) In the ormula: A, A and A are the structure matrix, auxiliary steam matrix and auxiliary water matrix respectively;α, α andα are the extraction coeicient vectors, auxiliary steam coeicient vectors and auxiliary water coeicient vectors respectively; q is pure heat matrix; b is eature vectors. Exergy loss stribution matrix o secondary-circuit thermal system. Accorng to the characteristics o the PWR nuclear power units thermal system,the exergy loss matrix equation is established: I = Eα + E α + Eα + e be (2) In the ormula: E is exergy stribution structure matrix; E, E are auxiliary steam exergy stribution matrix and auxiliary water stribution matrix respectively; e is pure exergy vector; be is exergy stribution eature vector. The inluence o extraction steam pressure loss on the extraction coeicient and exergy loss. Through to calculate the partial derivative or ormula No.1 and No.2, when extraction steam pressure loss changing, we can get the variation o extraction coeicient and exergy loss. The variation o extraction coeicient is: α = α w + α d The variation o exergy loss is: (3) I = I w + I d (4) In the ormula: α w and I w are the variation o extraction steam coeicient and exergy loss respectively when eed water temperature changing; α d and I d are the variation o extraction coeicient and exergy loss respectively when hydrophobic temperature temperature changing. The inluence o extraction steam pressure loss on the unit economy. The variation o power o the unit is: Wi Wi Wi = t + t (5) The variation o absolute internal eiciency is: 509

4 ηi ηi = t ηi + t The variation o absolute exergy eiciency is: (6) ηei ηei = t ηei + t (7) Calculate. Accorng to the partial erential mathematical model o steam-water stribution matrix equation and exergy loss stribution matrix equation, when extraction steam pressure loss o a eed water heater decreased by 5%,we can calculate that the variation o extraction steam coeicient, exergy loss and the unit economy. The calculation results as shown in table 1, table 2 and table 3. Table 1 The variation o extraction steam coeicient name No.1 No.2 No.3 No.4 No.5 No.6 No.7 α α α α α α α α α Table 2 The variation o exergy loss I 1 /kj I 2 /kj I 3 /kj I 4 /kj I 5 /kj I 6 /kj I 7 /kj I 8 /kj I 9 /kj Table 3 Unit Economy w i /kj η i η ei

5 Analysis. For heat recovery heater No. 1, No. 2, No. 3, when the extraction pressure loss o a heater changing, only extraction steam coeicient and exergy loss o heater No.i+1 and the lower pressure heater behind it are changed. For heat recovery heater No. 4, No. 5, No. 6, No. 7, when the extraction pressure loss o a heater changing, the extraction steam coeicient and exergy loss o all the heaters are changed. Summary 1) Because o the coupling o heat recovery system and reheat system, when the extraction pressure loss o heater No.4, No.5, No.6, No.7 changing, the parameters o all the heat recovery heater and reheat heater are changed. 2) The heater what has the largest inluence on the unit economy is No.4 low pressure heater. When the extraction steam pressure loss o No.4 heater was reduced by 5%, absolute internal eiciency and absolute exergy eiciency are increased by 0.031% and 0.069% respectively.so we should reduce the extraction steam pressure loss o No.4 heater. 3) The method what this article uses can be used in the quantitative analysis o PWR nuclear power unit,and provide a theoretical guidance or the operation o the PWR nuclear. Reerences [1] Wan-chao Liu: Energy Saving Theory o Power Plant Thermal System(Xi'an Jiao Tong University press, Xi'an 1994). [2] Jia-xuan Wang, Shu-ang Zhang: Exergy Method and Its Application in Thermal Power Plant(China Water Power Press, Beijing 1993). [3] Hong-ang Zhang, Lin-tie Fang,Song-eng Tian.Quantitative Analysis about the Inluence o Extraction Steam Pressure Loss to Exergy Loss on 1000MW Unit[J].Turbine Technology, 2012, 54(4): [4] Li-yun Fan, Pei-jie Zhang, Lin-tie Fang.Inluence o Extraction Steam Pressure Loss o heat recovery system on exergy loss stribution [J]. Energy Conservation, 2012, (6): [5] Yun-ze Li, Jun-jie Yan, Wan-chao Lin.The matrix analysis method o secondary circuit o PWR nuclear power unit [J].Thermal Power Generation, 2000, (4): [6] You-yin Xing, Zheng-hui Zhao, Jun-hui Xu.steam-water stribution matrix equation o secondary circuit o PWR nuclear power unit [J]. Turbine Technology, 2010,52(4). 511

660 MW. Vol. 31 No. 3 Mar NO x N /600 /620 45% 40% Fig. 1 Diagram of a principle thermal system for low temperature economizers 660 MW

660 MW. Vol. 31 No. 3 Mar NO x N /600 /620 45% 40% Fig. 1 Diagram of a principle thermal system for low temperature economizers 660 MW 31 1 2016 1 JOURNAL OF ENGINEERING FOR THERMAL ENERGY AND POWER Vol. 31 No. 3 Mar. 2016 1001-2060201603 - 0083-04 660 MW 310014 5 660 MW 2. 33 g / kwh / 1 000 Nm / kg TK223. 3 + 3 A DOI10. 16146 /j. cnki.