Recommended E-N charge modification (Second cycle PT-IP-350-C E-N demonstration load)

摘要

The original charge for the E-N core load at H reactor, consisting of five different types of charges, each group of five containing 199 .947 per cent enriched uranium E-pieces of six inch nominal length and 16 Li-Al I&E (N) pieces of four inch nominal length plus mixers, was intended to provide enough excess reactivity to operate the reactor at all times with reasonable but not excessive flexibility. During actual operation the excess reactivity observed has been somewhat greater than conservatively planned. In addition, a very slight long-term gain rather than the expected loss has been observed up to this time (73 MWD/column average exposure). On this basis, a modification of the original charge makeup has been determined which will permit increased conversion and operating efficiency.