Study on a temperature change phenomenon of gas flow into a negatively-pressured canister

Abstract

We have been investigating methods for detecting gas leaks from the canister of the concrete cask, which stores spent fuel, by using a temperature change of the canister surface at the time of the leak. This time, we investigated a temperature change inside and outside the canister when gas flowed into due to loss of containment in a negatively-pressured canister by using a small canister model with a simplified internal structure. The kind of internal gas, initial pressure conditions, gas mixing conditions, and a heat rate were used as parameters to clarify the temperature change phenomenon inside and outside the canister before and after the leak at negative pressure. Furthermore, the sensitivity of the leak detection method using the temperature change of the canister surface under each experimental condition was examined, and its practicability to the negatively-pressured canister was confirmed. In the case of the negative pressure, there is a concern that air may enter the canister and oxidize the fuel at loss of containment of the canister. However, using a double wall canister with inert gas filled between the canisters would solve this concern.