Nuclear fuel assembly top nozzle comprising hold-down means

The top nozzle comprises: an intermediate plate (26) axially positioned between an upper plate (24) and a lower plate (22), the intermediate plate being axially movable between an upper position and a lower position; one or more primary spring members (28) arranged to permanently push the intermediate plate (26) towards the upper plate (24); one or more spring members (30) arranged to push the intermediate plate (26) towards the upper plate (24) when the intermediate plate (26) is between a lower position and an intermediate position associated with the auxiliary spring members (30); and a preloading element (32) associated with each auxiliary spring member (30) and arranged such that the auxiliary spring members (30) abut against the upper plate (24) via the preloading element (32) when the intermediate plate (26) is located between an intermediate position and an upper position associated with said auxiliary spring members (30). 顶部喷嘴包括：轴向定位在上板(24)和下板(22)之间的中间板(26)，该中间板能在上部位置和下部位置之间轴向移动；被布置成永久地朝上板(24)推中间板(26