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The Influence of Impurity Water for CHF on the Downward Facing Boiling Surface


 In-Vessel Retention (IVR) strategy is one of the most important severe accident management strategies. The Critical Heat Flux (CHF) is an important key element in the IVR research. How to increase the CHF get more and more attention in the CHF research. This paper aims at the influence of the coolant with different impurity. Those impurity can fall into the coolant when the severe accident happens. In this experiment, the deionized water was used as the coolant. The experiment investigated the different impurity with boronic acid that has different concentration and the boronic acid water with different impurity, such as concrete, fiberglass and coating. The concrete can be fallen from the construction, the fiberglass can be fallen from the insulation cotton which cover the pipe and device, and the coating can be fallen from the devices and other constructions. When the accident happens, those impurity can fall from the construction, then fall into the coolant and influence the CHF of the outside surface of lower head. From the result of the experiment, the CHF with the boron acid water is higher than that only deionized water. The CHF with the impurity water depend on the concentration of the impurity. Lower concentration will increase the CHF when the higher concentration will decrease the CHF. Different impurity has different influence on CHF, we control the component of the coolant to improve the CHF.