Patent Number: 056278667
Section: claims

1. A fuel assembly for a nuclear reactor vessel, the fuel assembly comprising: a plurality of fuel rods;  at least one coolant rod;  a channel surrounding said plurality of fuel rods and said at least one coolant rod;  a lower tie plate supporting said plurality of fuel rods and said at least one coolant rod, said lower tie plate being supported by said channel such that said channel carries a load of said fuel assembly;  an upper tie plate disposed inside said channel and laterally supporting said plurality of fuel rods and said at least one coolant rod; and  connecting structure releasably connecting said upper tie plate and said channel, wherein said connecting structure comprises at least one extendible and retractable latch pin, said channel comprising a corresponding at least one aperture for receiving said latch pin,  wherein said upper tie plate comprises a bolt aperture adjacent said coolant rod that opens to a spring channel in said upper tie plate, the fuel assembly further comprising:  a plurality of fuel rods;  at least one coolant rod;  a channel surrounding said plurality of fuel rods and said at least one coolant rod;  a lower tie plate supporting said plurality of fuel rods and said at least one coolant rod, said lower tie plate being supported by said channel such that said channel carries a load of said fuel assembly;  a transition member partially disposed in said channel and adjacent said lower tie plate, said transition member being attached to said channel, wherein said lower tie plate rests on said transition member;  at least one bolt threadedly secured through said channel and said transition member; and  at least one channel clip fixed to said channel and inserted into a slot in said transition member, said at least one channel clip being partially disposed axially interior of said channel, thereby restricting axial displacement of said transition member relative to said channel. 2. A fuel assembly according to claim 1, wherein said connecting structure comprises two opposed extendible and retractable latch pins, said channel comprising a corresponding two opposed apertures for receiving said latch pins. 3. A fuel assembly according to claim 2, wherein said upper tie plate comprises two boss members each having a channel therein, each of said latch pins being movably disposed in said each of said channels, respectively. 4. A fuel assembly according to claim 3, further comprising two springs, one each disposed in each of said channels surrounding a respective one of said latch pins and urging said latch pins toward an extended position, said latch pins having a first outer periphery configured to be received in said apertures, respectively, and a second outer periphery, larger than said first outer periphery, configured to sit adjacent said channel in the extended position. 5. A fuel assembly according to claim 4, wherein each of said latch pins comprises a spring engaging surface delimiting said channels, respectively, said springs being disposed in said channels between an end surface of said channels and said spring engaging surfaces, respectively. 6. A fuel assembly according to claim 3, wherein said boss members are integral with said upper tie plate. 7. A fuel assembly according to claim 1, wherein said connecting structure comprises a channel guide fixed to said upper tie plate and disposed outside of said channel, said channel guide including at least one ear, wherein said channel comprises a corresponding at least one ear aperture configured to receive said at least one ear. 8. A fuel assembly according to claim 7, wherein said channel guide comprises two arms disposed at substantially 90.degree. and two ears, each fixed to a respective one of said two arms. 9. A fuel assembly according to claim 8, wherein said channel guide comprises two legs extending from ends of said two arms, respectively, said two ears each being fixed to one of said two legs, respectively. 10. A fuel assembly for a nuclear reactor vessel, the fuel assembly comprising: 11. A fuel assembly according to claim 10, comprising four channel clips fixed to each corner of said channel. 12. A fuel assembly according to claim 11, wherein said channel clips are welded to said channel.