PURPOSE: To obtain a guide tube in which a control rod cluster is exposed to a flowing coolant at the least extent by forming top ends of a guide cylinder and a sheath plate so as to exceed upwardly the lowermost guide plate and to extend far above toward an guide plate upper than the said one.
CONSTITUTION: A guide tube 7 is orderly arranged in a fuel assembly so that an lower guide tube 7b of the tube 7 is attached onto the upper reactor core plate 5. The guide tube 7 has an upper guide tube other than the lower guide tube 7b. At a rectangular tube shaped housing of the guide tube 7, two openings 15 for each piece are formed between a base plate 17 and a lower guide plate 16 and a coolant of the guide tube 7 can flow out from the openings 15 to the outside, changing its flow direction sidewise. Moreover, a guide tube 18 and a sheath plate 19 extends upwardly far above a lower guide plate 16 and ends at the lowermost intermediate guide plate 14a. Accordingly, a so-called 'continuous part' continues to an intermediate guide plate 14, not to the lower guide plate 16 at a periphery of the upper opening 15. By this constitution, control rods are prevented from being exposed directly to the coolant.
OTSUKA EIICHIRO
BAN MINORU
AJIKI KAZUHIDE
SHOMURA HIROKAZU
| JPS6224398B2 | 1987-05-28 | |||
| JPS5829879A | 1983-02-22 |
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