FAST-NEUTRON REACTOR FAST-NEUTRON REACTOR

摘要

1433373 Fuel elements V G ILJUNIN I A KUZNETSOV V M MUROGOV J V SILAEV and A N SHMELEV 14 May 1973 22767/73 Heading G6C A fuel element assembly for a fast reactor is divided, in the direction of coolant flow, into at least two sections of fissile material, the fuel in the section with a lower temperature of the coolant possessing a higher density of heavy nuclei, or a higher density of fissile isotopes. Such a fuel assembly, as shown, comprises two sections 3, 4 separated by a space 5 and each accommodating fuel elements 2 attached to a jacket 1 by means of diagrids 6. The coolant flows from section 3 to section 4, increasing in temperature as it does so. The fuel elements in section 3 may contain U or Pu metal fuel, while those in section 4 may contain Pu ceramic fuel. Alternatively, all the fuel elements may contain Pu ceramic fuel, those in section 3 containing fuel enriched to a greater extent than those in section 4. The fuel elements in sections 3 and 4 may also differ in their transverse cross-sections, those in section 3 having the greater diameter. In an alternative construction (not shown), the fuel elements extend the entire height of the fuel assembly, those portions of the fuel elements which are in the lower temperature section containing metal fuel and those in the higher temperature section containing ceramic fuel. A non-active material occupies the space in the fuel elements intermediate the fuel-containing sections.