高速実験炉「常陽」性能試験報告書 : パイルオシレ-タ試験(NT-61)

"JOYO" Start-up test report; Pile oscillator tests (NT-61)

三田 敏男*; 牧戸 正紀*; 大谷 秀二*; 佐野 健一*; 綱島 幹泰*; 村松 晴*; 山本 寿*

Sanda, Toshio*; not registered; not registered; not registered; not registered; not registered; Yamamoto, Hisashi*

高速実験炉「常陽」の動特性試験の一環としてパイルオシレータ試験を行った。本試験では,零出力から約50MWまでの出力上昇の各段階において,パイルオシレータ装置により正弦波状反応度変化を与え,中性子束,燃料出口温度,原子炉出口温度等の応答から伝達関数を求めた。測定周波数範囲は,0.001Hzから3Hzである。▲主な試験結果は,以下の通りである。▲1)零出力伝達関数は,測定値と計算値がよく一致した。▲2)高出力伝達関数測定結果から,原子炉は大きな負のフィードバック効果のため,安定であることが確認できた。▲3)フィードバック伝達関数および中性子束と燃料出口温度の伝達関数は,ほぼ同じ時定数(約3秒)をもつ1次遅れで近似できる。▲4)2次系の温度制御系の効果は,今回の測定(反応度幅約7￠では0.001Hz付近の低周波領域のみに限られた。▲中心燃料集合体出口温度計(熱電対)の時定数は,約32秒である。▲

As a Part of dynamics tests in the experimental fast breeder reactor "JOYO" pile oscillator tests were carried out. At some power levels, from zero power to about 50 MW, the transfer functions between sinusoidal reactivity change wich a pile oscillator equipment and the response of the neutron flux, the outlet temperatures of fuel assemblies, reactor outlet temperatures and etc., were measured. Measurements were made in the range from 0.001 Hz to 3Hz. Major results are as follows. (1)The agreement between the measured and calculated zero-power transfer function was satisfactory. (2)By the measurements of the at-power frequency responses, the stability of JOYO was confirmed and the large and negative feedback effects were obseved. (3)The feedback transfer function and the transfer function between the flux and the response of the outlet of the temperature of the center fuel assembly are approximately expressed by a first-order lag with the same time constant (about 3 seconds). (4)In those measurements, in which the reactivity change inserted in the reactor was about 7 cent (peak-to-peak), the effect of the coolant temperature controller in the secondary cooling loop was reflected only in so far as the measurements were made at so low frequency, around 0.001 Hz. (5)The time constant of the thermocouple of the center fuel assembly was about 3.2 seconds.