Decay heat removal by natural circulation of vacuum vessel coolant for ITER

• Published in: Journal of fusion energy Vol. 16; no. 1-2; pp. 37 - 44
• Main Authors: ISELI, M, BARTELS, H.-W, POUCET, A
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Heidelberg Springer 01.06.1997; Springer Nature B.V
• Subjects: Applied sciences; Circulation; Coolants; Cooling; Cooling systems; Decay; Energy; Exact sciences and technology; General, economic and professional studies; Heat exchangers; Heat losses; Mathematical models; Nuclear power plants; Radiation damage; Vacuum; Vessels; Tokamak; Temperature distribution; LOCA; Computation code; Reactor vessel; Thermal dissipation; Natural circulation; Modeling; Cooling by air; Nuclear fusion reactor; Heat exchanger; Vacuum chamber; Numerical simulation
• ISSN: 0164-0313; 1572-9591
• DOI: 10.1023/a:1022556827940

The decay heat-driven temperature transients of the in-vessel components following a postulated loss of all in-vessel cooling have been calculated. The resulting time-dependent heat load to the vacuum vessel is due to radiation from the backplate and convection of postulated steam between backplate and vacuum vessel. It is shown, that even for a failure of all in-vessel cooling and total loss of power, the ITER design can rely on passive decay heat removal by natural circulation in one of the two existing cooling loops of the vacuum vessel. A mathematical model describes the transient operating conditions and shows that the temperature established by natural circulation does not exceed 200°C at the maximum shut down heat load to the vacuum vessel. Therefore, no additional emergency cooling system is required if the existing heat exchanger is designed for natural circulation and a bypass is used during normal operation to maintain operation temperature.