「もんじゅ」1次主循環ポンプ(モックアップ)の試験(XIII); 低液位・無シールガス運転試験(2)

MONJU Primary prototype pump test

小池 茂*; 藤川 俊美*; 広瀬 文隆*; 松本 精夫*; 中本 香一郎*

not registered; not registered; not registered; not registered; not registered

「もんじゅ」一次主循環ポンプ(モックアップ)について,ナトリウム中静圧軸受の交換及び低液位対流防止板装着後,ポンプ内の最低液位(EsL)試験及び軸封無シールガス試験を実施し,以下の知見を得た。(1)ポンプ内の最低液位での運転,最低液位での無シールガス運転及び通常液位での無シールガス運転を実施し,一次系配管破損時及び格納容器隔離時におけるポンプの健全性が確認できた。(2)最低液位での運転で,アウターケーシング及びインナーケーシング周方向温度差が最大となる時間,安定するまでに要する時間及びその位置を確認した。(3)アウターケーシング及びインナーケーシングの周方向最大温度差は,時間とともに増大し,液位が低下するほど大きく,かつ温度差が最大となるまでの時間も早くなることが判った。(4)最低液位での運転で確認したアウターケーシングの最大変位量は,ポンプの許容変位量以下であり,運転上問題とならない。(5)低液位対流防止板を装着した方が,アウターケーシング及びインナーケーシング周方向温度差が最大となる時間が長くなり,かつアウターケーシング変位量もゆっくり増加するなど,ケーシング変形が緩和され低液位対流防止板の装着は有効である。(6)最低液位の状態でポニーモータを停止し,また,再起動したところ,問題なく立ち上げられることを確認した。

In-sodium test was carried out for MONJU primary prototype pump, having a new hydrostatic bearing and convection suppressing fin. The test parameters were sodium level in the pump and flow of the seal gas. The test results are summarized as follows. (1)The pump operated satisfactorily on each condition of low sodium level with and without seal gas and normal sodium level without seal gas. This shows the pump has the soundness even in the cases of primary piping broken and the seal gas stopped. (2)It was obtained from the low sodium level test that each time of radial temperature difference for both inner and outer casings was its maximum and stable respectively. (3)It was approved that the maximum radial temperature differences for both inner and outer casings were increased with the time passing and sodium level falling, and also approved that the time which the temperature differences became their maximum were short with sodium level falling. (4)Maximum displacement of outer casing was smaller than the approved value at the lowest sodium level test, so it seems there is no problem on the real pump operation. (5)The test showed that convection suppressing fin was useful why the displacement of the casings were suppressed, because the times of the maximum radial temperature differences of the casings were late and displacement of outer casing was increased slowly. (6)It was approved that the pony motor of the pump was stopped and started again satisfactorily at the lowest sodium level.