Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Aizawa, Kosuke; Tsuji, Mitsuyo; Kobayashi, Jun; Kurihara, Akikazu; Nakane, Shigeru*; Onuma, Hideyoshi*
no journal, ,
Thermal-hydraulic phenomena driven by natural circulation in a reactor vessel was investigated by using scaled model water experiments simulating a reactor vessel to enforce the safety and to optimize the design and operation of decay heat removal systems under normal operation and severe accident conditions. This paper shows the results of transient behavior under operations of dipped-type DHX and penetrated-type DHX to clarify the effect of operating multiple decay heat removal systems on natural circulation phenomena in reactor vessel. From the experimental results, it was confirmed that the maximum temperature temporarily increased compared to the maximum temperature in natural circulation steady state by operating the second DHX after the natural circulation steady state was maintained under the first DHX operation.
Hiyama, Tomoyuki; Aizawa, Kosuke; Kobayashi, Jun; Kurihara, Akikazu; Nagasawa, Kazuyoshi*; Onuma, Hideyoshi*
no journal, ,
The self-actuated shutdown system (SASS) is a device that passively detach the control rod in response to a temperature rise at the reactor core outlet by utilizing the property that the magnetism of a temperature sensing part disappears as the temperature rises. It is adopted in the advanced sodium-cooled fast reactor designed in Japan. In order to function the SASS effectively, it is important to efficiently guide high temperature fluid from the fuel assembly to the temperature sensing part, so the circumstance of temperature sensing part has a complicated shape such as fins. In order to improve the SASS performance evaluation method, we plan to carry out the full-scale experiment to understand phenomena and acquire data for code validation. In this report, the water experiment was performed on the full-scale model that simulates from the outlets of the fuel assemblies to the SASS flow collector, and flow phenomena around the temperature sensing part was analyzed from the data obtained by PIV measurement.