Abstract: A jet pump including a riser as a coolant supply tube, an inlet mixer forming a turn-around path for the coolant, a diffuser, and a jet pump beam provided with a bolt fixing device is disclosed. The bolt fixing device includes: a head bolt of a jet pump beam for pushing and supporting the inlet mixer from an upper side of the riser, the head bolt being provided with a polygonal head portion; a lock cap provided on the polygonal head portion of the head bolt; a body housing disposed on an upper surface of the jet pump beam and adapted to accommodate the lock pin; a plurality of tapered external teeth formed on an outer peripheral side surface of the lock cap; and a plurality of internal tooth-shaped grooves formed to the body housing to fix the head bolt of the jet pump beam.

Abstract: A jet pump including a riser as a coolant supply tube, an inlet mixer forming a turn-around path for the coolant, a diffuser, and a jet pump beam provided with a bolt fixing device is disclosed. The bolt fixing device includes: a head bolt of a jet pump beam for pushing and supporting the inlet mixer from an upper side of the riser, the head bolt being provided with a polygonal head portion; a lock cap provided on the polygonal head portion of the head bolt; a body housing disposed on an upper surface of the jet pump beam and adapted to accommodate the lock pin; a plurality of tapered external teeth formed on an outer peripheral side surface of the lock cap; and a plurality of internal tooth-shaped grooves formed to the body housing to fix the head bolt of the jet pump beam.

Abstract: A jet pump is provided with a riser as a coolant supply tube, an inlet mixer forming a turn-around path for the coolant, a diffuser and a jet pump beam provided with a bolt fixing device. The bolt fixing device includes: a head bolt of a jet pump beam for pushing and supporting the inlet mixer from an upper side of the riser, the head bolt being provided with a polygonal head portion; a lock cap provided on the polygonal head portion of the head bolt to be slidable in an axial direction thereof and integrally rotatable; a body housing disposed on an upper surface of the jet pump beam and adapted to accommodate the lock pin; a plurality of tapered external teeth formed on an outer peripheral side surface of the lock cap; and a plurality of internal tooth-shaped grooves formed to the body housing so as to be selectively engaged with the external teeth of the lock cap so as to fix the head bolt of the jet pump beam.