Jet Pump Assembly

The jet pumps (Figure 3.9) are located in the annular region between the core shroud and the vessel inner wall. Each pair of jet pumps is supplied driving flew from a single riser pipe. The jet pump assembly is composed of two jet pumps and contains no moving parts. 

Jet pumps are stainless steel and nickel base alloy assemblies, which provide coolant flow to the reactor core for forced convection cooling. Each jet pump assembly consists of seven major subassemblies. These are the recirculation riser, two inlet mixers, two holddown beams, and two diffusers. A typical jet pump assembly is illustrated in Figure 2-13. 

Within the BWR core region, the jet pump assemblies experience high velocity as well as restricted flow regions. Since the flow in other regions is lower, consequences of erosion corrosion of less concern and an accompanying reduction in section has little impact. There has been no evidence of erosion corrosion in the jet pump throat area which would be... 

Each BWR jet pump assembly consists of a riser assembly, two diffuser assemblies, and two inlet-mixer assemblies. The exit of the inlet-mixer is connected to the diffuser through a slip joint and the entrance is connected to the top of the riser transition piece. The riser restrainer brackets couple the two inlet-mixers on either side of the riser pipe and support the iidet-mixer through three-point contact provided by two set screws and the inlet-mixer wedge. This three-point contact provides support for the inlet-mixer, which increases the stiffness of the jet pump assembly, and reduces the potential for abnormal vibration. 

Jet Pump Assembly BWRVIP-41 BWRVIP-03 BWRVIP-51 BWRVIP-62/-79... 

GE SIL 629, Inlet Mixer Wedge damage in BWR Jet Pump Assembly , July 11... 

BWR Vessel and Internals Project, BWR Jet Pump Assembly Inspection and Flaw Evaluation Guidelines (BWRVIP-41), EPRI Report TR-108728, October 1997. 

Preparation of Nitric Acid by Oxidizing Ammonia. Assemble an apparatus as shown in Fig. 90. Pour a 2% ammonia solution into flask 1. Put a loose layer of freshly roasted platinized asbestos into the middle of tube 2 over a length of 4-5 cm. Pour a neutral litmus solution or several drops of methyl red into flask 3 and connect the short tube of this flask to water-jet pump 4. Heat the platinized asbestos slightly with the flame of a gas burner and pass through it... 

Assemble an apparatus as shown in Fig. 95. Thoroughly dry all parts of the apparatus prior to the experiment. What should the calcium chloride tube be filled with Connect the wash bottle (or a U-tube) to the water-jet pump. Put red phosphorus into a spoon... 

Preparation of Sodium Peroxide. Assemble the arrangement shown in Fig. 117. Pour a little vaseline oil into wash bottle 1 and leave bottle 2 empty. Put 2-3 g of cleaned metallic sodium into porcelain boat 3 and place it into quartz or refractory glass tube 4. Cover the tube with asbestos and switch on the water-jet pump connected to the arrangement (ZrasZaZZ protective bottles ahead of the pump . Heat the part of the tube where the boat with the sodium is with a gas burner flame. When the sodium ignites, reduce the heating. Suck... 

Nuclear Boiler Assembly. This assembly consists of the equipment and instrumentation necessary to produce, contain, and control the steam required by the turbine-generator. The principal components of the nuclear boiler are (1) reactor vessel and internals—reactor pressure vessel, jet pumps for reactor water circulation, steam separators and dryers, and core support structure (2) reactor water recirculation system—pumps, valves, and piping used in providing and controlling core flow (3) main steam lines—main steam safety and relief valves, piping, and pipe supports from reactor pressure vessel up to and including the isolation valves outside of the primary containment barrier (4) control rod drive system—control rods, control rod drive mechanisms and hydraulic system for insertion and withdrawal of the control rods and (5) nuclear fuel and in-core instrumentation,... 

Reactor Assembly. This assembly (Fig. 3) consists of the reactor vessel, its internal components of the core, shroud, top guide assembly, core plate assembly, steam separator and dryer assemblies and jet pumps. Also included in the reactor assembly are the control rods, control rod drive housings and the control rod drives. 

Malfunctioning pump assembly, improperly located jets, damaged jet system If metal system, check and rectify if glass system check for particulate material. If necessary, empty the fluid, clean the pump, and replace with new fluid. 

In November 1996, cracks were discovered in 2 of 10 jet pump riser assembly elbows of a non-U.S. BWR after 25 years of service. The cracks were detected by visual examination (VT-1) during in-service inspection. As result, GE issued Service Information Letter (SIL) 605, Jet Pump Riser Cracking, dated December 6, 1996 [5.20], which provides recommendations for inspection and detection of jet pump riser cracks. 

In January, 1997, during enhanced VT-1 inspection as recommended by GE SIL 605, three crack indications were found in 2 of the 10 jet pump riser elbows at LaSalle Unit 2. The U.S. NRC issued Information Notice 97-02, Cracks Found in Jet Pump Riser Assembly... 

USNRC Information Notice 97-02, Cracks Fuound in Jet Pump Riser Assembly Elbows at Boiling Water Reactors , February 6, 1997. 

IE Bulletin 80-07 - BWR Jet Pump Beam Assembly Failure, U.S. NRC (Office of Inspection and Enforcement), April 17, 1980. 

NRC IE Bulletin 80-07 BWR Jet Pump Beam Assembly Failure Provides requirements to address jet pump holddown beam cracking [6.2]... 

NRC Information Notice 97-02 Cracks Found in Jet Pump Riser Assembly Elbows at Boiling Water Reactors Provides information to alert licensees that cracking has been detected in a jet pump riser assembly at a location not previously known to have cracks. [6.13]... 

Fig. 9.6, Sectional view of the Grand Gulf boiling water reactor (courtesy of General Electric Company and Nuclear Engineering International). A, Vent and head spray B, steam dryer C, steam outlet D, core spray outlet E, steam separators F, feedwater inlet G, feedwater sparger H, L.P. coolant injection inlet J, core spray pipe K, core spray sparger L, top guide M, jet pump N, core shroud O, fuel assemblies P, control blade Q, core plate R, jet pump water inlet S, recirculation water outlet T, vessel support skirt U, control rod drives V, in-core flux monitor.

In 1989, the steam-water power reactor concept was presented by Alekseev and colleagues working in the former USSR [16]. The use of steam-water mixture for the reactor cooling is a key feature of the concept. There are two versions of the steam-water mixture preparation and distribution system. In one, the steam is supplied externally by steam blowers to the RPV and it mixes with feedwater in the special nozzle mixers set at the fuel assembly inlet. In the other, the steam is circulated in the RPV by jet pumps. The steam-water mixture is prepared in the jet pumps. The diagram of the steam-water power reactor is shown in Fig. B.24 [3]. There is no description on the feasibility of steam-water mixture generation. The plant system is indirect cycle. The primary pressure is 16.0 MPa. The core inlet and outlet temperatures are 347 and 360°C, respectively. The core inlet quality is 40%. The average void fraction of the core is estimated to be 93%. The core average coolant density is estimated to be 0.14 g/cm. It should be pointed out that the technical and safety problems will be similar to those of the steam cooled FBR. 

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