Reactor cavity cooling system

Some of the experimental activities are undergoing to verify design tools such as the pebble heat transfer (Lee,2007), the reactor cavity cooling system heat transfer (Cho, 2006). 

Safety Perhaps superior, i) PCU and process heat loop have no role in heat removal safety systems. Safety system heat removal provided by shutdown cooling system and reactor cavity cooling system, ii) Rate of transport of tritium to chemical plant is reduced. 

Principal Component REACTOR CAVITY COOLING SYSTEM Reactor Cavity Cooling Panels... 

C (2912 F) during depressurized core heat removal by the Reactor Cavity Cooling System (RCCS). Selected reflector elements in both the central and side reflector contain channels for top entry control rods and for nuclear instrumentation. Nominal reactor design parameters are given in Table 4.1-1, and in Section 5.1. 

Each well extends vertically upward from the accessible area beneath the reactor vessel to the opposite of the upper portion of the reactor core. The wells are located in the inlet air stream of the Reactor Cavity Cooling System (RCCS) to assure that the neutron detectors are not exposed to undesirable temperature transients. The atmosphere in the wells is air at ambient pressure. 

DBE-4. which is a control rod withdrawal with Reactor Cavity Cooling System (RCCS) cooling, results in internals graphite temperatures essentially the same as AOO-2. Structural support and heat path functions are not affected. 

Tl e reactor vessel is surrounded by a reactor cavity cooling system, which provides totally passive decay heat removal. A separate cooling system provides decay heat removal for refuelling activities. 

Accompany with the RVCS, a shutdown cooling system(SCS) is proposed in the paper to provide a simple and reliable decay heat removal during normal shutdown period. The system is shown in Fig 3. It consists of an auxiliary blower, a cooler as well as a recuperator. Because the cooler and recuperator are also the parts of the RPV cooling system(RVCS), SCS is simple and its equipments have multi-function. The decay heat removal under the accidental conditions is depends on the passive reactor cavity cooling system. The SCS proposed in this paper therefore is not safety concerned. 

Thermal inertia can slow the temperature rise in the reactor core however, decay heat removal is ultimately required. The thermal capacity of the 2400 MW(t) AHTR core is more than a factor of four greater than the 600 MW(t) GT-MHR, while maintaining a peak core temperature of 1160°C at 50 hours in the AHTR. The acceptable thermal power of the AHTR is then limited by the peak decay-heat removal capacity of the RVACS, potentially supplemented by a DRAGS. The 600 MW(t) GT-MHR reactor cavity cooling system (RCCS) has a peak capacity that matches the decay heat output at the time of peak core temperature 50 hours after loss of cooling. To achieve the same 50-h duration at 2400 MW(t), the AHTR RVACS/ DRAGS system must have a heat removal capacity four times that of the GT-MHR. 

Backup heat removal system. The cost of the decay-heat removal system (reactor-cavity cooling system and variations) is assumed to scale with thermal power from the S-PRISM values by a factor of(2400/1000)° = 2.12. 

In the event that normal heat removal systems fail, heat is transferred to the reactor cavity cooling system via a combination of convection, conduction, and radiation. In the event that the cavity cooling system is unavailable, decay heat is transferred to the surroundings, primarily via radiation. 

Decay heat removal Shutdown cooling system Reactor cavity cooling system Active Passive - If cavity cooling fails, heatup of environment without overheating fuel... 

Decay heat removal Reactor Cavity Cooling System Passive - See design basis accidents... 

The GT-MHR has two active, diverse active heat removal systems, the PCS and the SCS that can be used for the removal of decay heat. In the event that neither of these active systems is available, an independent passive means is provided for the removal of core decay heat. This is the reactor cavity cooling system (RCCS) that surrounds the reactor vessel (Figure 5.15). For passive removal of decay heat, the core power density and the annular core configuration have been designed such that the decay heat can be removed by conduction to the pressure vessel (Figure 5.16) and transferred by... 

Passive heat removal is ensured from the fuel to the RPV via the core structures and on to the reactor cavity cooling system (RCCS). 

Two other cooling systems are available for utilization or removal of primary system energy the core conditioning system (CCS) and the reactor cavity cooling system (RCCS). The CCS serves the functions of removal of core decay heat when the Brayton cycle is not operating and the provision of helium flow through the core for reactor heat-up purposes during start-up operations [XIV-11]. 

The ongoing joint United States/Russian Federation project to develop and construct a version of the GT-MHR to consume surplus weapons plutonium is an important element of commercial GT-MHR development. The major systems, structures and components of the GT-MHR, including the power conversion system, reactor vessel and internals, and reactor building, can be developed and demonstrated through this project. The primary alterations to the plutonium consumption design are expected to be in the reactor core and possibly the reactor cavity cooling system, with the remainder of the commercial GT-MHR drawing directly from the plutonium consumption version. 

The systems for normal heat removal at power, normal shutdown heat removal, and passive decay heat removal are shown in Fig. XV-16. The reactor cavity cooling system is a passive natural circulation system that is normally operating and can be monitored to assure continuous operability. 

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