Transient Fuel Behavior and Failure Condition in the CABRI-2 Experiments

None

佐藤 一憲 ; Lemoine, F.*; Struwe, D.*

Sato, Ikkenn; Lemoine, F.*; Struwe, D.*

CABRI-2プログラムでは、Phenix炉で照射された中空/中実燃料を用いて、制御棒引き抜き事象に相当する緩慢な過出力型条件、及びシビアアクシデントの一つであるULOF(Unprotected Loss of Flow)型の過渡条件での試験を実施した。これらの試験からは、燃料条件や過渡条件に応じた破損/非破損データが得られ、これと既存CABRI試験やその他の実験的情報、さらには解析評価からの知見を総合することにより、高速炉燃料の過渡条件下での挙動、及び破損限界に係わる知見をまとめた。

In the CABRI-2 program, 12 tests were performed under various transient conditions covering a wide range of accident scenarios using two types of pre-irradiated Fast Breeder Reactor (FBR) fuel pins with different smear densities and burn-ups. For each fuel, a non-failure-transient test was performed and it provided basic information such as fuel thermal condition, fuel swelling and gas release. From the failure tests, information on failure mode, failure time and axial location was obtained. Based on this information, failure conditions such as fuel enthalpy and cladding temperature were evaluated. These failure conditions were compared with the CABRI-1 tests in which different fuels as well as different transient conditions were used. This comparison, together with supporting information available from existing in-pile and out-of-pile experiments, allowed an effective understanding on failure mechanisms depending on fuel and transient conditions. It is concluded that Pellet Cladding