Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Heat-up Calculation for the Auxiliary Feed Water Pump Room at Ulchin Units 3 and 4 for Loss of HVAC Accidents

HVAC 상실사고시 울진원전 3/4 호기의 보조급수펌프 격실 온동상승 평가

  • Yoon, Churl (Nuclear Hydrogen Reactor Technology Development Division, Korea Atomic Energy Research Institute) ;
  • Park, Jin-Hee (Integrated Risk Assessment Division, Korea Atomic Energy Research Institute) ;
  • Hwang, Mee-Jeong (Integrated Risk Assessment Division, Korea Atomic Energy Research Institute) ;
  • Han, Sang-Hoon (Integrated Risk Assessment Division, Korea Atomic Energy Research Institute)
  • 윤철 (한국원자력연구원 수소생산원자로기술개발부) ;
  • 박진희 (한국원자력연구원 종합안전평가부) ;
  • 황미정 (한국원자력연구원 종합안전평가부) ;
  • 한상훈 (한국원자력연구원 종합안전평가부)
  • Received : 2011.08.01
  • Accepted : 2012.02.10
  • Published : 2012.05.01
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Abstract

Computational Fluid Dynamics (CFD) analysis has been performed to estimate the air temperature inside an Auxiliary Feed Water (AFW) Motor-Driven (MD) pump room for the case where there is loss of Heating, Ventilation, and Air-Conditioning (HVAC). A transient calculation for the closed pump room without cooling by any HVAC system shows that the volume-averaged air temperature reaches around $60^{\circ}C$ for a transient period of 8.0 h. From previous studies, the external air and surface boundary temperatures are assumed to increase slowly starting from an initial temperature of $35^{\circ}C$. For the cases where the door is opened at 2, 4, and 6 h after the initiation of HVAC failure, the average air temperature promptly drops by about $4^{\circ}C$ when the door is opened and then slowly increases. The current calculations based on the CFD technique predict the rate of increase of air temperature to be lower than that determined by previous conservative calculations on the basis of a lumped model.

난방, 환기 및 공기조절(HVAC) 기능이 상실된 사고의 경우, 보조급수를 위한 모터-구동 펌프격실의 온도상승을 전산유체역학 분석을 통해 평가하였다. 닫힌 펌프격실의 과도 계산결과, 8 시간 동안 공간-평균된 공기온도는 $60^{\circ}C$ 정도의 상승이 예상된다. 외기 온도 및 외부 온도는 이전 계산결과로부터 초기 $35^{\circ}C$에서 시작하여 서서히 증가한다고 가정하였다. 격실 문이 사고발생 후 약 2, 4, 그리고 6시간 경과 시점에서 열릴 경우, 체적-평균 격실 내가 온도는 약 $4^{\circ}C$의 즉각적인 하강이 나타나며 이후 서서히 온도가 상승하는 장기 거동을 보인다. 전산유체역학을 적용한 현재의 상세 해석결과는 이전의 집중(lumped) 모델을 사용한 보수적인 계산결과에 비해 낮은 격실온도 상승률을 예측한다.

Keywords

Acknowledgement

Supported by : 한국과학재단

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