b'C H A P T E R 12R EA CT O R S B E G ET R EA CT O R SThe ETR fuel was arranged in a rectan-gular grid with holes here and there forinsertion of loops and capsules. Manyof the ETR holes were large enough tocontain entire fuel elements, not justsamples, and the experiments couldoperate with their own cooling systemsindependent of the reactors own cool-ing system. Like the MTR, the ETRhad a companion low-power reactor,the ETR Critical Facility (ETRC), inwhich the power-perturbing qualities ofproposed experiments could be mea-sured safely in advance before beingtested in the ETR.The ETR generated a neutron flux fourtimes greater than the MTR. It wentcritical for the first time on September INEEL 57-498419, 1957. It would serve many of theMTRs old customers, including theU.S. Navy, but the new kid on theNRTS block was the U.S. Air Force,and many of the special ETR loops hadbeen designed to test the fuels requiredfor a special airplane. 24The Noble SkyOh come with meto watch the first RADON INEEL 59-5513When the stars ARGON Above. The ETR being assembled, top removed. Fuel elements were lifted from reactor core and sent through aAs the day KRYPTON chute into the canalall under shielding water. This improved safety and convenience over MTR methods.And if the morn be cloudy Below. The ETR with experiments in progress.You wont ZENON.MTR shift supervisors log: May 6, 19521 1 5'