Passive residual heat removal system

Passive Residual Heat Removal System (PRHRS)... 

Passive Residual Heat Removal system X 2 HX within the In-containment Refueling Water Storage Tank (IRWST) Permanently connected to the pnmary circuit... 

Decay heat removal Passive Residual Heat Removal System (PRHR) Passive Non-LOCA heat removal... 

Passive residual heat removal system (PRHRS) X 3 channels 1 channel on the reactor, 2 channels to the secondary circuit 1 loops... 

Density locks (thermal barriers), siphon breakers, and wet thermal insulation Prestressed concrete reactor vessel Long-term passive residual heat removal system Reactivity control without control rods... 

Passive residual heat removal system X 2 trains, using the steam generators... 

Passive Residual Heat Removal System X Heat transfer from primary coolant to CV water by natural circulation of coolant in S.G. 

Passive Residual Heat Removal System X 2 100% trains of natural-circulation water loops permanently connected to the primary circuit and cooled by external air. Only one non-static component, passive type (special check valve), 400% redundant... 

The in-containment refuelling water storage tank must provide the heat sink for the passive residual heat removal system. 

The passive residual heat removal system is designed to remove decay heat from the reactor coolant system. 

This potential design improvement consists of increasing the design pressure of the steam generator secondary side and safety valve set point to the degree that a steam generator tube mpture will not cause the secondary system safety valve to open. The design pressure w ould have to be increased sufficiently such that the combined heat capacity of the secondary system inventory and the passive residual heat removal system could reduce the reactor coolant system... 

A scaled-down test facility has been established comprehensive tests using this facility will produce data on the whole system interaction, performance behaviour of the self-controlled pressurizer (PZR), indirect performance effect of passive residual heat removal system (PRHRS), natural circulation effects, etc. 

Figure 1-2 shows the simplified schematic diagram of the SMART nuclear steam supply system (NSSS) and exhibits the safety systems and the primary system as well as auxiliary systems. The engineered safety systems designed to function passively on demand consist of a reactor shutdown system, passive residual heat removal system, emergency core cooling system, safeguard vessel and reactor overpressure protection system. 

Application of passive residual heat removal systems. 

Figure 14.16 Schematic diagram of the new-concept passive residual heat removal system of molten salt reactors using the sodium heat pipe.

Sun, L., Yan, C., Fa, D., Wang, N., 2014. Conceptual design and analysis of a passive residual heat removal system for a 10 MW molten salt reactor experiment. Progress in Nuclear Energy 70, 149-158. 

Wang, C., Guo, Z., Zhang, D., Qiu, S., Tian, W., 2013a. Transient behavior of the sodium-potassium alloy heat pipe in passive residual heat removal system of molten salt reactor. Progress in Nuclear Energy 68, 142—152. 

Park, H.-S., Choi, K.-Y., Cho, S., Yi, S.-Y., Park, C.-K., Chung, M.-K., 2008. Experimental study on the natural circulation of a passive residual heat removal system for an integral reactor following a safety related event. Annals of Nuclear Energy 35, 2249—2258. 

Wenbin, Z., Yanping, H., Zejun, X., Chuanxin, R, Sansan, L., 2014. Experimental research on passive residual heat removal system of Chinese advanced PWR. Science and Technology of Nuclear Installations 2014. Article ID 325356, 8 p. 

The safety system (Fig. 20.21) of SMART includes a shutdown cooling system, residual heat removal system, safety injection system, reactor overpressure protection system, and emergency boron injection tank. Each of the four independent passive residual heat removal systems with 50% capacity can remove the core decay heat through natural circulation at any design basis events. This feature can keep the core undamaged for 72 h without any corrective action by operators in a design basis accident (Kim et ah, 2014). 

PRHRS Passive residual heat removal system... 

Passive residual heat removal system from the core via steam generators to the atmosphere as the ultimate heat sink (so called SPOT) plays an important role in the core melt frequency reduction mentioned above. The design basis for this system is that in case of station blackout during the most unfavorable atmosphere conditions the heat removal capacity with account for the failure of one channel shall amount to not less than 2% of the reactor rated power. The heat removal at the initial stage of the accident is performed due to partial water evaporation from the secondary side via steam generator relief valves to the atmosphere. 

---