| 摘要 |
<p>857,318. Controlling nuclear reactors. ATOMIC ENERGY OF CANADA Ltd. Feb. 10, 1959 [March 5, 1958], No. 4700/59. Class 39(4). A nuclear reactor has a reserve of highly enriched fuel to overcome Xe<SP>135</SP> poisoning when starting up after shutdown. Plates 5 of an alloy of U<SP>235</SP>, U<SP>233</SP> or Pu<SP>239</SP> with Al, Mg or Zr can be lowered in guides 6 into the centre of a reactor, and then withdrawn when the reactor starts up. The plates have a total excess reactivity of about 1%. They are cooled by D 2 O which also acts as moderator ; the reactor coolant is also D 2 O and the fuel is natural or slightly enriched uranium. The reactor is controlled by varying the moderator level and by partial insertion of the plates 5 for a short time, position indicators 11 being provided. The operating mechanism is housed in a gas tight space containing He.</p> |
