• Title, Summary, Keyword: PCCS

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Optimal design of passive containment cooling system for innovative PWR

  • Ha, Huiun;Lee, Sangwon;Kim, Hangon
    • Nuclear Engineering and Technology
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    • v.49 no.5
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    • pp.941-952
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    • 2017
  • Using the Generation of Thermal-Hydraulic Information for Containments (GOTHIC) code, thermal-hydraulic phenomena that occur inside the containment have been investigated, along with the preliminary design of the passive containment cooling system (PCCS) of an innovative pressurized water reactor (PWR). A GOTHIC containment model was constructed with reference to the design data of the Advanced Power Reactor 1400, and report related PCCS. The effects of the design parameters were evaluated for passive containment cooling tank (PCCT) geometry, PCCS heat exchanger (PCCX) location, and surface area. The analyzed results, obtained using the single PCCT, showed that repressurization and reheating phenomena had occurred. To resolve these problems, a coupled PCCT concept was suggested and was found to continually decrease the containment pressure and temperature without repressurization and reheating. If the installation level of the PCCX is higher than that of the PCCT, it may affect the PCCS performance. Additionally, it was confirmed that various means of increasing the external surface area of the PCCX, such as fins, could help improve the energy removal performance of the PCCS. To improve the PCCS design and investigate its performance, further studies are needed.

Color Expression in Produce Design applying PCCS Color System -Focusing on Male Bike Helmet Products- (제품디자인에서 PCCS 색체계를 적용한 색채표현 -남성용 자전거 헬멧 제품을 중심으로-)

  • Kim, Young-Seok
    • The Journal of the Korea Contents Association
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    • v.12 no.10
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    • pp.82-92
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    • 2012
  • This study is on the color expression of 100 male bike helmet products examining color image scale with high preference, PCCS color system applied color analysis and influence of color in decision making. The targets are all domestically distributed male bike helmets. The image scale was divided into 4 sections (Soft, Hard, Dynamic and Static) by color, and color image scale was analyzed to top 10 priority products. And analysis according to PCCS color system was made. Finally, questionnaire survey was carried out to analyze the influence of color on purchase decision making. The questionnaire survey was carried out to male in 20s~50s who were the member of 18 bike clubs in S agent in Seoul. 414 out of 422 sheets except for 8 insufficient ones were used. The results can be divided into 3.

Numerical Investigation on Natural Circulation in a Simplified Passive Containment Cooling System (단순화된 피동 원자로건물 냉각계통 내 자연순환에 관한 수치적 연구)

  • Suh, Jungsoo
    • Journal of the Korean Society of Safety
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    • v.33 no.3
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    • pp.92-98
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    • 2018
  • The flow of cooling water in a passive containment cooling system (PCCS), used to remove heat released in design basis accidents from a concrete containment of light water nuclear power plant, was conducted in order to investigate the thermo-fluid equilibrium among many parallel tubes of PCCS. Numerical simulations of the subcooled boiling flow within a coolant loop of a PCCS, which will be installed in innovative pressurized-water reactor (PWR), were conducted using the commercially available computational fluid dynamics (CFD) software ANSYS-CFX. Shear stress transport (SST) and the RPI model were used for turbulence closure and subcooled flow boiling, respectively. As the first step, the simplified geometry of PCCS with 36 tubes was modeled in order to reduce computational resource. Even and uneven thermal loading conditions were applied at the outer walls of parallel tubes for the simulation of the coolant flow in the PCCS at the initial phase of accident. It was observed that the natural circulation maintained in single-phase for all even and uneven thermal loading cases. For uneven thermal loading cases, coolant velocity in each tube were increased according to the applied heat flux. However, the flows were mixed well in the header and natural circulation of the whole cooling loop was not affected by uneven thermal loading significantly.

Preliminary Analysis of the Thermal-Hydraulic Performance of a Passive Containment Cooling System using the MARS-KS1.3 Code (MARS-KS1.3을 이용한 피동원자로건물냉각계통 열수력 성능 예비분석)

  • Bae, Sung Hwan;Ha, Tae Wook;Jeong, Jae Jun;Yun, Byong Jo;Jerng, Dong Wook;Kim, Han Gon
    • Journal of Energy Engineering
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    • v.24 no.3
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    • pp.96-108
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    • 2015
  • A passive containment cooling system has been designed to remove the heat inside a containment during accidents without external power supply. In this work, the PCCS was introduced in the APR1400 plant to replace the containment spray system and, then, the thermal-hydraulic performance of the PCCS was analyzed using the system thermal-hydraulic computer code, MARS. A double-ended cold-leg break accident, which is known to induce the maximum pressure in the containment, is simulated, where the thermal hydraulics of the PCCS, the reactor coolant system, and the containment are simultaneously simulated. The results of the calculations showed that the PCCS can replace the existing spray system and that the containment building and its internal structure also play a very important role for the heat removal during the accident. Some sensitivity calculations were carried out to evaluate the model uncertainty and the effects of design parameters. The limitations of the PCCS are also discussed.

Derivation of a Simplified Heat Transfer Correlation for AP 600 Passive Containment Cooling System

  • Chung, Bum-Jin
    • Journal of Energy Engineering
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    • v.7 no.1
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    • pp.122-130
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    • 1998
  • A simplified heat transfer model for the cooling capability of the AP 600 PCCS is proposed I this paper. As the PCCS domain is covered with very thin and long water film, it is phenomenologically divided into 3 regions; water entrance effect region, asymptotic region, and air entrance effect region. As the length of the asymptotic region is estimated to be over 90% of the whole domain, the phenomena in the asymptotic region is focused. Using the analogy between heat and mass transfer phenomena in a turbulent situation, a new dependent variable combining temperature and vapor mass fraction was defined. The similarity between the PCCs phenomena in the asymptotic region and the buoyant air flow phenomena on a vertical heated plate is derived. Using the similarity, the simplified heat transfer correlations for the interfacial heat fluxes and the ratios of latent heat transfer to sensible heat transfer were established. To verify the accuracy of the correlation, the results of this study were compared with those of other numerical analyses performed for the same configuration and they are well within the range of 15% difference.

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Numerical Study of the Heat Removal Performance for a Passive Containment Cooling System using MARS-KS with a New Empirical Correlation of Steam Condensation (새로운 응축열전달계수 상관식이 적용된 MARS-KS를 활용한 원자로건물 피동냉각계통 열제거 성능의 수치적 연구)

  • Jang, Yeong-Jun;Lee, Yeon-Gun;Kim, Sin;Lim, Sang-Gyu
    • Journal of Energy Engineering
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    • v.27 no.4
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    • pp.27-35
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    • 2018
  • The passive containment cooling system (PCCS) has been designed to remove the released decay heat during the accident by means of the condensation heat transfer phenomenon to guarantee the safety of the nuclear power plant. The heat removal performance of the PCCS is mainly governed by the condensation heat transfer of the steam-air mixture. In this study, the heat removal performance of the PCCS was evaluated by using the MARS-KS code with a new empirical correlation for steam condensation in the presence of a noncondensable gas. A new empirical correlation implemented into the MARS-KS code was developed as a function of parameters that affect the condensation heat transfer coefficient, such as the pressure, the wall subcooling, the noncondensable gas mass fraction and the aspect ratio of the condenser tube. The empirical correlation was applied to the MARS-KS code to replace the default Colburn-Hougen model. The various thermal-hydraulic parameters during the operation of the PCCS follonwing a large-break loss-of-coolant-accident were analyzed. The transient pressure behavior inside the containment from the MARS-KS with the empirical correlation was compared with calculated with the Colburn-Hougen model.

FOLLOW-UP OBSERVATIONS TOWARD PLANCK COLD CLUMPS WITH GROUND-BASED RADIO TELESCOPES

  • LIU, TIE;WU, YUEFANG;MARDONES, DIEGO;KIM, KEE-TAE;MENTEN, KARL M.;TATEMATSU, KEN;CUNNINGHAM, MARIA;JUVELA, MIKA;ZHANG, QIZHOU;GOLDSMITH, PAUL F;LIU, SHENG-YUAN;ZHANG, HUA-WEI;MENG, FANYI;LI, DI;LO, NADIA;GUAN, XIN;YUAN, JINGHUA;BELLOCHE, ARNAUD;HENKEL, CHRISTIAN;WYROWSKI, FRIEDRICH;GARAY, GUIDO;RISTORCELLI, ISABELLE;LEE, JEONG-EUN;WANG, KE;BRONFMAN, LEONARDO;TOTH, L. VIKTOR;SCHNEE, SCOTT;QIN, SHENGLI;AKHTER, SHAILA
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.79-82
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    • 2015
  • The physical and chemical properties of prestellar cores, especially massive ones, are still far from being well understood due to the lack of a large sample. The low dust temperature (< 14 K) of Planck cold clumps makes them promising candidates for prestellar objects or for sources at the very initial stages of protostellar collapse. We have been conducting a series of observations toward Planck cold clumps (PCCs) with ground-based radio telescopes. In general, when compared with other star forming samples (e.g. infrared dark clouds), PCCs are more quiescent, suggesting that most of them may be in the earliest phase of star formation. However, some PCCs are associated with protostars and molecular outflows, indicating that not all PCCs are in a prestellar phase. We have identified hundreds of starless dense clumps from a mapping survey with the Purple Mountain Observatory (PMO) 13.7-m telescope. Follow-up observations suggest that these dense clumps are ideal targets to search for prestellar objects.

Development of stability maps for flashing-induced instability in a passive containment cooling system for iPOWER

  • Lim, Sang Gyu;No, Hee Cheon;Lee, Sang Won;Kim, Han Gon;Cheon, Jong;Lee, Jae Min;Ohk, Seung Min
    • Nuclear Engineering and Technology
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    • v.52 no.1
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    • pp.37-50
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    • 2020
  • A passive containment cooling system (PCCS) has been developed as advanced safety feature for innovative power reactor (iPOWER). Passive systems are inherently less stable than active systems and the PCCS encountered the flashing-induced instability previously identified. The objective of this study is to develop stability maps for flashing-induced instability using MARS (Multi-dimensional Analysis of Reactor Safety) code. Firstly, we conducted a series of sensitivity analysis to see the effects of time step size, nodalization, and alternative MARS user options on the onset of flashing-induced instability. The riser nodalization strongly affects the prediction of flashing in a long riser of the PCCS, while time step size and alternative user options do not. Based on the sensitivity analysis, a standard input and an analysis methodology were set up to develop the stability maps of PCCS. We found out that the calculated equilibrium quality at the exit of the riser as a stability boundary above 5 kW/㎡ was approximately 1.2%, which was in good agreement with Furuya's results. However, in case of a very low heat flux condition, the onset of instability occurred at the lower equilibrium quality. In addition, it was confirmed that inlet throttling reduces the unstable region.