atw 2018-04v6
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<strong>atw</strong> Vol. 63 (<strong>2018</strong>) | Issue 4 ı April<br />
OPERATION AND NEW BUILD 234<br />
increases compared to the existing<br />
IHX loop.<br />
The following is the major comparison<br />
of the result of reference<br />
model and bypass mode model.<br />
Mass flow IHX loop Bypass Mode Loop<br />
Heat Exchanger 1 49839 50000<br />
Steam Generator 2 208359 214580<br />
Heat Exchanger 3 902043 918581<br />
| | Tab. 3.<br />
IHX Loop and Bypass Mode IHX Loop: Mass Flow Comparison.<br />
Pumping power<br />
When IHX loop and bypass modeadded<br />
IHX loop were compared, mass<br />
flow of m 10 and m 14 in the bypass<br />
mode-added loop was greater compared<br />
to the mass flow of m 5 and m 8 in<br />
the existing loop, as shown in Table 3.<br />
IHX loop<br />
(MWt)<br />
| | Tab. 4.<br />
IHX Loop and Bypass Mode IHX loop: Pumping Power Comparison.<br />
As shown in Table 4, depending on<br />
the difference of mass flow value,<br />
pumping power used in the pump also<br />
can be high in steam generator 2 and<br />
heat exchanger 3. However, although<br />
pumping power is higher in the bypass<br />
IHX loop, by reheating, efficiency of<br />
steam generator 2 increased from<br />
53.79 % to 54.4 %, and that of heat<br />
exchanger 3 increased from 45.83 %<br />
to 45.87 %; accordingly, it is seen that<br />
the value of Power increased. As a<br />
result, Net Power that considered<br />
pumping power in Total Power was<br />
178.6 MWt in the present IHX<br />
loop, but the IHX loop to which<br />
bypass mode was added increased<br />
to 185.3 MWt, as shown in Table 5.<br />
| | Tab. 5.<br />
IHX loop and Bypass mode IHX loop: Power Comparison.<br />
Bypass mode loop<br />
(MWt)<br />
Steam Generator 2 1.091 1.123<br />
Heat Exchanger 3 9.82 10<br />
Power<br />
IHX loop<br />
(MWt)<br />
Bypass mode loop<br />
(MWt)<br />
Heat Exchanger 1 37.37 37.37<br />
Steam Generator 2 94.63 99.7<br />
Heat Exchanger 3 57.46 59.34<br />
Net Power 178.6 185.3<br />
Since the assumption was that<br />
constant heat was supplied from the<br />
primary system, it is seen that the<br />
efficiency of the bypass model where<br />
net power is high, and it is judged that<br />
efficiency optimization model can be<br />
formulated by detailed design.<br />
4 Conclusion<br />
In this study, VHTR system was<br />
modelled for supplying high temperature<br />
heat, by distribution, produced in<br />
the high temperature gas furnace to<br />
hydrogen producing equipment and<br />
power generation equipment.<br />
Provided that high temperature<br />
gas- cooled reactor is located in<br />
primary system, the secondary system<br />
where hydrogen production and<br />
power supply are possible were<br />
explained. The helium that flows in<br />
the nuclear reactor first passes<br />
through the HX (heat exchanger)<br />
whose purpose is the production of<br />
hydrogen, and secondly and thirdly<br />
pass through the steam generator<br />
composed of super critical carbon<br />
dioxide cycle, and heat exchanger,<br />
respectively, producing the process<br />
heat and power. In order to analyze<br />
existing IHX loop model and bypass<br />
mode-added IHX loop model, the<br />
present authors studied the input &<br />
output conditions and output change<br />
of each steam generator and heat<br />
exchanger, and based on this result,<br />
by designing IHX loop in the power<br />
production part in detail, the authors<br />
performed the calculation of thermodynamic<br />
physical value and efficiency<br />
at each point. Additionally, the<br />
authors studied the change regarding<br />
electricity output and efficiency<br />
according to bypass mode, when<br />
reheating cycle is added, the possibility<br />
on the efficiency optimization<br />
was proposed.<br />
References<br />
[1] Kim. Y. W., 2015, Nuclear Hydrogen<br />
Production Technology development<br />
Using Very High Temperature Reactor,<br />
Trans. Korean Soc. Mech. Eng. C, Vol. 3,<br />
No. 4, pp. 299~305.<br />
[2] Chang. J. H., 2006, Current Status of<br />
Nuclear Hydrogen Development,<br />
Journal of Energy Engineering, Vol.15,<br />
No.2, pp. 127~137.<br />
[3] Lee. S. I., 2015, Heat Balance Study<br />
on Integrated Cycles for Hydrogen<br />
and Electricity Generation in VHTR,<br />
Transaction of the KNS Spring Meeting.<br />
[4] Sung. H. C., 2012, Development of<br />
Ultra-Supercritical (USC) Power Plant,<br />
Trans. Korean Soc. Mech. Eng. B,<br />
Vol. 36, No.2, pp.205~210.<br />
[5] Yeom Chung-seop, Im Dong-ryeol,<br />
Lee Jung-ik, 2014, Trend of Electricity<br />
Generation Technology using supercritical<br />
CO 2 , Institute for Advanced<br />
Engineering, KIC News, Volume 17,<br />
No.1.<br />
[6] K.C.Cotton,1998, Evaluating and<br />
Improving Steam Turbine Performance,<br />
2 nd edition, Cotton Fact Inc.<br />
[7] F-Chart Software, 2016,<br />
Engineering Equation Solver,<br />
http://www.fchart.com/ees/<br />
[8] NGNP Conceptual Design Report/Steam<br />
Cycle Modular Helium Reactor<br />
(SC-MHR) Demonstration Plant,<br />
Table 3-6 SC-MHR Conceptual Design<br />
Point Design Parameter.<br />
[9] SangIL Lee, Yeon Jae Yoo, Gyunyoung<br />
Heo, Soyoung Park, Yeon Kwan Kang,<br />
Heat Balance Study on Integrated<br />
Cycles for Hydrogen and Electricity<br />
Generation in VHTR-Part 2, Korean<br />
Nuclear Society Autumn Meeting,<br />
Oct 28-30, 2015.<br />
Authors<br />
SangIL Lee<br />
YeonJae Yoo<br />
Deok Hoon Kye<br />
Department of Nuclear Team<br />
Power & Energy Plant Division<br />
Hyundai Engineering Company<br />
Seoul, Korea<br />
Gyunyoung Heo<br />
Eojin Jeon<br />
Soyoung Park<br />
Department of Nuclear<br />
Engineering<br />
Kyung Hee University<br />
Yongin Korea<br />
Operation and New Build<br />
Heat Balance Analysis for Energy Conversion Systems of VHTR ı SangIL Lee, YeonJae Yoo, Deok Hoon Kye, Gyunyoung Heo, Eojin Jeon and Soyoung Park