Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Decay Heat Removal Systems

Functional and hardware relationships between systems are considered in selecting the order of event tree headings. Systems that depend on the operation of other systems in order to perform their function should be listed after the other systems. For example, the decay-heat removal system... [Pg.116]

Thermal loads upon the process heat exchanger do not allow rapid temperature change rates. Therefore in case of the demand for a decay heat removal system after a fast shutdown of the reactor, an auxiliary cooling system should be used rather than the main cooling system. In addition, much of the decay heat would be removed via the core surfaces to the liner cooling system [10]. [Pg.36]

In 1982, the Research Center Jiilich presented the conceptual design of a 50 MW(th) nuclear process heat plant with a pebble-bed HTGR, named AVR-II, for which a safety-related study has been conducted [29]. Its characteristic features are a slim steel pressure vessel, no separate decay heat removal system, shutdown and control system via reflector rods, surface cooling system, and a simplified containment. The safety of the reactor is principally based on passive system feamres. [Pg.43]

The AHTR 500 is a further development of the HTR-MODUL design with 500 MW(th). The helium coolant is heated up from 330 to 950 °C. The system pressure is 2 MPa. The new feature of this reactor design is a central graphite column to provide an additional heat sink. It contains a passive decay heat removal system on the basis of natural convection which runs also during normal operation. No intermediate circuit is foreseen for the connection with a coal gasification system [41]. [Pg.69]

Two concepts of a He - He intermediate heat exchanger for a heat rating of 125 - 170 MW have been selected. For both, a 10 MW test plant has been operated in the KVK loop verifying the operation of reformers with convective helium. A 10 MW decay heat removal system cooler, hot gas ducts including insulation and liner, hot gas valves, and a steam generator were other components of the KVK loop. Furthermore, a helium purification system was operated in a bypass of the main system. Starting in 1982, the KVK facility was operated for 18,400 h with approx. 7000 h above 900 C [28]. Hot gas duct with internal insulation was operated at temperatures up to 950 °C. The KVK experimental loop has demonstrated reliability and availability even of newly developed components. [Pg.73]

The top shield includes roof slab and two rotatable plugs. Warm roof concept is adopted for top shield to minimise sodium deposition in the annular gaps. The roof slab is a box type structure filled with concrete as the shielding material. It supports the main vessel, primary sodium pumps, IHX, and direct reactor heat exchangers (DHX) of the decay heat removal system. Use of liquid metal seals has been avoided in order to reduce the rotatable support... [Pg.186]

The primary stem pipes coimected to the RPV are of small sized diameters, and the largest one is SOmm of diameter for those of the safety valve and the emergency decay heat removal system. A large LOCA over SOmm diameter, therefore, is not necessary to be postulated. The elevations of the all pipes connected to the RPV are near the primary coolant pumps as a result of possible upper part of Ae RPV. [Pg.89]

Fig. 5 Reactor cooling system with decay heat removal system... Fig. 5 Reactor cooling system with decay heat removal system...
Long term coolant Low pressure coolant injection system (2) Re-circulation coolant system (1) Static residual heat removal system (2) (Natural circulates) Emergency decay heat removal system (3) (Natural circulates)... [Pg.98]

Decay heat removable system failed open of isolation valve 1.1 X 10 ... [Pg.99]

The engineered safety system of MRX is greatly simplified by adoption of the water-filled containment and the passive decay heat removable system relied on the natural circulation. Comparing the numbers of the sub-systems and equipment in the engineered safety system with other nuclear plants, the number of is decreased significantly. [Pg.105]

In the 4S, following the loss of off-site power, the primary loop shifts to natural circulation. The pump in the secondary loop of the decay heat removal system does not work assuming the loss of emergency power following loss of off-site power. Under such conditions, the secondary coolant operates in natural circulation mode and natural air-cooling operates in the air cooler. Thus, a passive heat removal circuit is established. [Pg.167]

Fig. 11 Primary Coolant Temperature Response upon Loss of Decay Heat Removal System... Fig. 11 Primary Coolant Temperature Response upon Loss of Decay Heat Removal System...
Evolution of Passive Decay Heat Removal Systems in Similar Size Vessels Enables Design of Larger Reactors... [Pg.14]

Patalano, G., Apostolakis, G. E., Hejzlar, P. 2008. Risk informed design changes in a passive decay heat removal system. Fmc/. Technol. 163 191-208. [Pg.685]

Core height /diameter Fuel pin dia / No of pins per SA Number of PSP Number of IHX Number of sec loops Number of SG per loop Number of TG Na temp at reactor inlet Na temp at reactor outlet Steam condition at SG outlet In-vessel fuel handling Spent fuel storage Reactor shutdown systems Decay heat removal systems Containment building Reactor site Reactor life... [Pg.86]

A shutdown level-1 PSA has almost completed. The reliability of the decay heat removal system (DHRS) during the plant shutdown (refueling and maintenance) was evaluated. There are several system trains out of service because of the scheduled maintenance so that it reduces redundancy of the safety functions. We considered several candidates of accident management (AM) measures as an operator recovery action under accident condition. As a result of this study, it concluded that these AM candidates were effective for the DHRS to maintain high reliability in cooperation with a long grace period. [Pg.136]

KALIMER has enhanced safety features with the use of metallic fuel, Self-Actuated Shutdown System (SASS), Gas Expansion Module (GEM) in the core, and Passive Safety Decay Heat Removal System (PSDRS). Utilization of these enhanced safety features eliminates the need for diverse and redundant engineered safety systems and KALIMER accommodates unprotected anticipated transients without scram (ATWS) events without operator action, and without the support of active shutdown, shutdown heat removal, or any automatic system without damage to the plant and without jeopardizing public safety. [Pg.139]

SOME ISSUES OF APPROXIMATE MODELING OF FAST REACTOR DECAY HEAT REMOVAL SYSTEMS... [Pg.174]

Considering the progress in studies on fast reactor decay heat removal systems, the following points may be noted ... [Pg.174]

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. [Pg.90]

Sodium fast reactor. Sodium-cooled fast reactors are low-pressure, high-temperature reactors. Because these characteristics are similar to the AHTR, the AHTR plant design shares many features with this class of reactors, and specifically the General Electric S-PRISM, for which a considerable R D investment has already been expended. These features inelude overall facility design and decay heat removal systems. [Pg.93]

RVACS/DRACS test loop (research). RVACS and DRAGS decay heat removal systems have been developed and tested for sodium-cooled fast reactors. However, the AHTR RVACS/DRACS will operate at significantly higher temperatures. Test loops are required to provide integrated experimental data to qualify design codes for higher temperatures. [Pg.96]


See other pages where Decay Heat Removal Systems is mentioned: [Pg.203]    [Pg.394]    [Pg.35]    [Pg.202]    [Pg.8]    [Pg.4]    [Pg.79]    [Pg.86]    [Pg.92]    [Pg.96]    [Pg.96]    [Pg.122]    [Pg.243]    [Pg.49]    [Pg.90]    [Pg.90]    [Pg.21]    [Pg.29]    [Pg.29]    [Pg.30]    [Pg.77]    [Pg.77]    [Pg.93]    [Pg.395]    [Pg.395]    [Pg.13]   
See also in sourсe #XX -- [ Pg.285 , Pg.288 , Pg.335 , Pg.439 ]




SEARCH



Decay heat

Heat removal

Heat removal system

Heat systems

Removal systems

© 2024 chempedia.info