Core vessel

Provide instrumentation and controls to process the signals from two ex-core vessel neutron detectors in each well. 

The core metallic internal which consistesof the metallic core vessel, biological shielding structure, bottom support plate and enhanced plate, top pressing plate will be manufactured by the Shanghai No. 1 Machine Works. 

The flow diagram of RVCS is shown in Fig 2 The system consists of a RPV recuperator(RVR), a RPV cooler(RVC), orifices and valves As illustrated in Fig 1 and Fig 2, a bypass flow is extracted from the blower outlet and flows downward through the tube side of the RVR, which is installed in the annular region outside the IHX, and is cooled down from 550t to 250 Then the cold bypass flow enters an annular channel outside the RVR and flows upward into the shell side of a little cooler (RVC) and is cooled form 250°c to 190 t , the 190 c cold gas enters the gap between the RPV and core vessel and is heated by the two vessel from 190 to 220x At last, the 220 X bypass gas flows upward through some vertical pipes and comes into the RVR shell side and returns to the blower inlet The main technical data of the RVCS is given in table 4... 

Fig. 2.6. Elevation view of AHTR core, vessels, and internals.

A metallic core vessel, which is supported in the lower part of the reactor pressure vessel, acts as supporting structure for the ceramic core internals. The cover of the core vessel is constructed as a radiation shield (so-called top thermal shield) to provide access to the area above the core vessel for maintenance work. This area is filled with stagnant helium during operation. 

The system is basically similar to many existing liquid systems. The core vessel accommodates cores up to 5 ft. in diameter by S ft. tall and a wide variety of grid structures. A moderator dump system and separate storage is employed. Heating and insulation allow operation up to a tenqmrature of 600 F. Poison rods are cable actuated and can be used in any lattice position. 

In the assiemby, the appropriate core vessel was situated within a Wider reflector vessel of 84-cm diam. This vessel was built p fimn aluminum-alloy ring sections. 

Fig. 1. Geometry of SHEBA core vessel. All material is Type 304 stainless steel except as noted.

Fig. 2. Dose rates at 3 m from center of SHEBA core vessel.

Design basis lifetime for reactor core, vessel and structures... 

Fuel lifetime, mass balances offuel materials, design basis lifetime of reactor core, vessel ... 

The projected service lifetime for the reactor core, vessel and equipment is 60 years. 

The period between refuelling sis estimated to be 5500 effective full power days (EFPD). Design basis lifetime for reactor core, vessel and structures... 

Pressure vessel Core vessel and pipes Passive/ very low pressure... 

The metallic internal structures are composed of the core vessel, upper and lower support plates, holddown plates and a positioning plate. They provide support and housing to the ceramic internal structures and also transmit the mechanical loads coming from the fuel pebble bed and the ceramic internals to the reactor pressure vessel. 15CrMoR is selected as the material for most metallic core internal structures. The total weight of the metallic core internals is about 72.5 t. 

The general design of both types of light water reactor has already been illustrated diagrammatically in Fig. 7.1. The layout of the main components of the primary circuit of a PWR is shown in Fig. 12.3. The circuit consists of the core vessel itself, together with the four steam generators and main... 

The design basis lifetime for HTR-PM core, vessel and structures is 60 years. 

The core vessel was a welded steel cylinder with a hemispherical bottom and a lid, the latter penetrated by vertically arranged steel pipes that form leak-tight channels. Core vessels of two wall thicknesses were used, 0.5 cm and 0.3 cm. 

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