Jet pump and reactor

A jet pump comprising:

• a nozzle apparatus having a header portion disposing a first pipe member forming a suction fluid passage for introducing a suction fluid, inside the header portion, and including an annular passage, which surrounds the first pipe member, for introducing a motive fluid, and a nozzle portion installed to the header portion, surrounding the first pipe member, and forming an ejection outlet, which is communicated with the annular passage formed in the header portion, for ejecting the motive fluid;
• a throat for passing the motive fluid ejected from the ejection outlet and the sucked suction fluid in a direction from an upper end portion to a lower end portion of the throat;
• a diffuser into which the lower end portion of the throat is inserted;
• and
• a second pipe member, one end of which is connected to the nozzle apparatus, forming a motive fluid passage for introducing the motive fluid to the annular passage in the header portion;
• wherein the nozzle apparatus is disposed above a bell mouth installed on the upper end portion of the throat, apart from the bell mouth;
• wherein the first pipe member is disposed inside the motive fluid passage formed in the second pipe member through the one end of the second pipe member, and an opening for the suction fluid passage is formed on an outer surface of the second pipe member and opened toward outside of the second pipe member;
• wherein the motive fluid passage is formed in a way that the motive fluid flowing toward the one end of the second pipe member hits the first pipe member diagonally in the axial direction of the first pipe member;
• and
• wherein a cross-sectional area of a fluid passage formed in the throat diminishes toward the lower end portion of the throat which is inserted into the diffuser.

A jet pump comprising:

• a nozzle apparatus for ejecting a motive fluid;
• a throat for passing the motive fluid ejected from the nozzle apparatus and a sucked suction fluid in a direction from an upper end portion to a lower end portion of the throat;
• and
• a diffuser into which the lower end portion of the throat is inserted;
• wherein the nozzle apparatus is disposed above a bell mouth installed on an upper end portion of the throat, apart from the bell mouth;
• the nozzle apparatus has a first tubular member;
• a second tubular member disposed in the first tubular member, apart from the first tubular member;
• a fluid passage forming member disposed in the first tubular member, and installed to an upper end portion of the second tubular member;
• a plurality of passage members fixing one end portion and an other end portion to the first and the second tubular members;
• the plurality of passage members being disposed in a circumferential direction of the nozzle apparatus;
• and an annular ejection outlet is formed between a lower portion of the first tubular member and a lower portion of the second tubular member;
• a suction passage formed in each of the passage members, for introducing the suction fluid from outside of the nozzle apparatus to inside of the passage members, communicates with an inner region formed in the second tubular member,
• an annular motive fluid passage for introducing the motive fluid, across which each of the passage members is disposed, is formed between the first tubular member, and the second tubular member and the fluid passage forming member, and communicated with the annular ejection outlet,
• an ejection outlet-side portion of the driving fluid passage slopes inward toward a lower end of the nozzle apparatus, and,
• wherein a cross-sectional area of a fluid passage formed in the throat diminishes toward the lower end portion of the throat which is inserted into the diffuser.

A boiling water reactor having a reactor vessel and a plurality of jet pumps installed in the reactor vessel, which jet pumps are for feeding coolant to a core formed in the reactor vessel,

• wherein each of the jet pumps comprise:
• a nozzle apparatus for ejecting a motive fluid;
• a throat for passing the motive fluid and a sucked suction fluid in a direction from an upper end portion to a lower end portion of the throat;
• and a diffuser into which the lower end portion of the throat is inserted;
• wherein the nozzle apparatus has a nozzle base member, and a plurality of nozzles installed to the nozzle base member and forming a plurality of narrowing portions, in which a fluid passage cross-sectional area of a motive fluid passage formed in the plurality of nozzles is reduced;
• and
• wherein a cross-sectional area of a fluid passage formed in the throat diminishes toward the lower end portion of the throat which is inserted into the diffuser.