Fuel assembly for a pressurized water reactor
A fuel assembly for a pressurized water nuclear reactor includes a multiplicity of fuel rods which extend in a longitudinal direction and are guided in a plurality of spacers that are spaced apart from one another axially. The spacers of an upper region have a lower flow resistance in a transverse direction perpendicular to the longitudinal direction, than the spacers of a lower region.
1. A fuel assembly for a pressurized water reactor, the fuel assembly comprising:
upper and lower adjoining regions as a whole extending over the entire fuel assembly;
a plurality of mutually axially separated spacers disposed in said upper region and a plurality of mutually axially separated spacers disposed in said lower region;
a multiplicity of fuel rods extended in a longitudinal direction and guided in said spacers; and
each of said spacers of said upper region having a lower flow resistance in a transverse direction perpendicular to said longitudinal direction than each of said spacers of said lower region.
2. The fuel assembly according to claim 1 , wherein said spacers have a lateral edge formed by edge webs, and said edge webs of said spacers of said upper region cover a smaller area than said edge webs of said spacers of said lower region, in said transverse direction.
3. The fuel assembly according to claim 2 , wherein said spacers include a plurality of intersecting inner webs, and said inner webs of said spacers of said upper region cover a smaller area than said inner webs of said spacers of said lower region, in said transverse direction.
4. The fuel assembly according to claim 2 , wherein only said spacers of said upper region have openings formed in said edge webs.
5. The fuel assembly according to claim 3 , wherein only said spacers of said upper region have openings formed in said edge webs.
6. The fuel assembly according to claim 2 , wherein said edge webs of all of said spacers have openings formed therein, and a total area of said openings in said edge webs of said spacers of said upper region is larger than a total area of said openings in said edge webs of said spacers of said lower region.
7. The fuel assembly according to claim 3 , wherein said edge webs of all of said spacers have openings formed therein, and a total area of said openings in said edge webs of said spacers of said upper region is larger than a total area of said openings in said edge webs of said spacers of said lower region.
8. The fuel assembly according to claim 3 , wherein only said spacers of said upper region have openings formed in said inner webs.
9. The fuel assembly according to claim 5 , wherein only said spacers of said upper region have openings formed in said inner webs.
10. The fuel assembly according to claim 7 , wherein only said spacers of said upper region have openings formed in said inner webs.
11. The fuel assembly according to claim 2 , wherein said spacers have inner webs, and only said spacers of said upper region have openings formed in said inner webs.
12. The fuel assembly according to claim 4 , wherein wherein said spacers have inner webs, and only said spacers of said upper region have openings formed in said inner webs.
13. The fuel assembly according to claim 6 , wherein wherein said spacers have inner webs, and only said spacers of said upper region have openings formed in said inner webs.
14. The fuel assembly according to claim 3 , wherein said inner webs of all of said spacers have openings formed therein, and a total area of said openings in said inner webs of said spacers of said upper region is larger than a total area of said openings in said inner webs of said spacers of said lower region.
15. The fuel assembly according to claim 5 , wherein said inner webs of all of said spacers have openings formed therein, and a total area of said openings in said inner webs of said spacers of said upper region is larger than a total area of said openings in said inner webs of said spacers of said lower region.
16. The fuel assembly according to claim 7 , wherein said inner webs of all of said spacers have openings formed therein, and a total area of said openings in said inner webs of said spacers of said upper region is larger than a total area of said openings in said inner webs of said spacers of said lower region.
17. The fuel assembly according to claim 8 , wherein said inner webs of all of said spacers have openings formed therein, and a total area of said openings in said inner webs of said spacers of said upper region is larger than a total area of said openings in said inner webs of said spacers of said lower region.