圧力波挙動測定試験 データ集(1)

Pressure wave propagation tests simulating sodium-water reaction accidents by using slow explosives

坂野 耿介*; 清水 一民*; 吉江 伸二*

not registered; not registered; not registered

本試験の目的は無液面型蒸気発生器を持つ2次主冷却系におけるナトリウム-水反応時の初期スパイク圧の伝播による,圧力開放板の破裂持性とそれに伴う伝播圧力波の減圧効果を把握することである。試験は実証炉設計例の2次主冷却系を1/5スケールにて製作し,初期スパイク圧を低爆速火薬を用いて模擬し,ナトリウムを水で置き換えて実施した。圧力開放板の破裂特性を高速撮影により可視化した結果,開放板は約1300m/sで到達した初期スパイク圧により変形を開始し,これより1.1msecで反転後,水噴出し,1.7msecで4分割され約4msecで完全開口した。圧力開放板の破裂挙動によって,放出系配管内の伝播圧力波は約30%の減圧効果があった。但し,破裂後であっても放出系配管内圧力波は持続し,その時間は蒸気発生器内の反応点のものと同程度であった。本試験によって圧力開放板の破裂特性が初めて明らかにされ,減圧効果を評価することができた。そしてこれらの成果はナトリウム-水反応解折コードの検証用データになる。

The present tests have been executed for simulating an initial pressure spike of sodium-water reactions in a secondary coolant system with no cover-gas type steam generators and for grasping burst characteristics of rupture discs and diminution effects of propagated pressure waves. The tests have been performed by using slow-explosives to simulate the initial pressure spike under water instead of sodium in the 1/5-scaled down secondary coolant system model of a Large Scale Fast Breeder Reactor. The high-speed photographing indicated that the rupture disc became to deform by the initial pressure spike propagated at about 1300 m/s, to jet water after buckling in 1.1 msec later, to split to 4 parts in 1.7 msec, and to be perfectly opened itself in about 4 msec. About 30 percent of the pressure diminution was shown for the propagated pressure wave in the discharge piping by the burst behavior of the rupture disc. After the disc was burst, however, the pressure wave held in the discharge piping and the duration time was the same as that of the reaction point in the steam generator. For the first time, the burst characteristics of rupture discs were identified and the diminution effect was evaluated by the tests. These data are useful for verification of analytical codes of sodium-water reaction.