Submission Title
Presentation Type
Poster
Start Date
18-12-2018 1:00 PM
Abstract
Retention of corium inside the CV and cool it by calandria vault water is essential to mitigate severe accidents in PHWRs. The thermal failure of CV can be prevented by effective decay heat removal on the outer surface of CV using vault water, which depends on the heat transfer behaviour from the outer surface of CV to the vault water. Determination of limiting heat removal capability of vault water through outer surface of calandria vessel is very important. Since, the calandria vessel has a very large diameter and length, the bottom most part of the calandria vessel almost behaves as a flat surface with downward natural convection heat transfer. In order to estimate critical heat flux (CHF) in this configuration with local boiling, experiments need to be carried out on a downward facing flat plate simulating the bottom portion of PHWR calandria vessel.
Studies on critical heat flux in downward-facing boiling on flat plate is very limited in literature. Limited experiments on CHF on curved surfaces have been conducted in the past owing to its importance for in vessel retention in PWRs. Since CHF depends on the geometry and material of construction, operating parameters, the results of above experiments cannot be extrapolated to PHWRs. In order to estimate limiting heat removal capability for PHWR configuration with local boiling on outer surface of CV, experiments were carried out on downward facing flat plate and estimated the CHF of downward facing flat plate and compared the CHF value with other experiments performed for curved surface.
Recommended Citation
Prasad, Sumit V. and Nayak, A. K. (2018). "Experimental evaluation of critical heat flux in downward-facing boiling on flat plate relevant to in-vessel retention in Indian PHWRs," Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety. https://newprairiepress.org/asemot/2018/fullprogram/4
Experimental evaluation of critical heat flux in downward-facing boiling on flat plate relevant to in-vessel retention in Indian PHWRs
Retention of corium inside the CV and cool it by calandria vault water is essential to mitigate severe accidents in PHWRs. The thermal failure of CV can be prevented by effective decay heat removal on the outer surface of CV using vault water, which depends on the heat transfer behaviour from the outer surface of CV to the vault water. Determination of limiting heat removal capability of vault water through outer surface of calandria vessel is very important. Since, the calandria vessel has a very large diameter and length, the bottom most part of the calandria vessel almost behaves as a flat surface with downward natural convection heat transfer. In order to estimate critical heat flux (CHF) in this configuration with local boiling, experiments need to be carried out on a downward facing flat plate simulating the bottom portion of PHWR calandria vessel.
Studies on critical heat flux in downward-facing boiling on flat plate is very limited in literature. Limited experiments on CHF on curved surfaces have been conducted in the past owing to its importance for in vessel retention in PWRs. Since CHF depends on the geometry and material of construction, operating parameters, the results of above experiments cannot be extrapolated to PHWRs. In order to estimate limiting heat removal capability for PHWR configuration with local boiling on outer surface of CV, experiments were carried out on downward facing flat plate and estimated the CHF of downward facing flat plate and compared the CHF value with other experiments performed for curved surface.
