Containment pressure suppression

Fission product containment Pressure suppression pool Passive... 

Severe Accidents Containment Pressure suppression tanks Passive ... 

Containment Pressure Suppression (CPSS) X Bubbling through water storage tank... 

The HPCS system can be tested during normal plant operation or when the plant is shut down. During normal plant operation, pump suction is from the condensate storage tank with a full flow return line to the condensate storage tank. During plant shutdown, pump suction is from the primary containment pressure suppression pool with a full flow return line to the suppression pool. The control system provides for the automatic transfer to the service mode upon the presence of ECC demand signal. 

Additional pressure suppression system - this characteristic applies to reactor units having a containment pressure suppression system additional to the one above one. Data providers should choose the appropriate option from the same multiple-choice menu ice condenser, water condenser, pressure suppression pools, containment spray, N/A. 

Number of containment spray pumps - this characteristic applies to reactor units with an active containment/confinement spray system. Thus this characteristic identifies units using this active containment pressure suppression system, and also specifies the number of containment spray pumps. For units with no active containment spray system data providers should enter "N/A". 

In Japan, "Evaluation Guide of Dynamic Loads on Pressure Suppression System of BWR (Mark I Containment)" and "Evaluation Guide of Dynamic Loads on Pressure Suppression System of BWR (Mark II Containment)" have been established, and loads on containment pressure suppression systems are specified based on those Guides for structural design. 

Finally, could the Author say what condensation efficiency he would underwrite with a fully contained, pressure suppression form of containment ... 

On his final point, without doing some large-scale experimental work or having access to results from elsewhere covering the appropriate conditions, I would not care to underwrite any figure for condensation, efficiency for a fully contained pressure suppression system. 

Eig. 9. Principle of pressure suppression containment. Steam from a broken pipe escapes from the dryweU through a vent and is condensed in the water... 

It has a large reactor vessel surrounded by a passive pressure-suppression containment system that includes large water pools that inject by gravity to ensure water covers the core. 

MKI The Mark I containment consists of two separate structures (volumes) connected by a series of l.irae pipes One volume, the dry well, houses the reactor vessel and primary system components. The other i oUmic is a torus, called the wetwell, containing a large amount of water used for pressure suppression and as, i heai sink. The Brunswick units use a reinforced concrete structure with a steel liner. All other M,uk 1 cnni.un ments are free-standing steel structures, The Mark I containments are inerted during plant oper.mon i. prevent hydrogen combustion. 

Liquids under pressure (pipeline leaks, pump seal failures, etc.), will be thrown some distance from the point source, while atmospheric leakages will emit at the point of release. The other characteristic of liquid releases is their flash points. High flash point liquids, not operating above their flash point temperatures, are inherently safer than low flash point liquids. Most liquid fires are relatively easy to contain and suppress while gas fires are prone to explosion possibilities if extinguished and source points are not isolated. 

Figure 49-2 BWR Mark II over and under pressure suppression containment system. Chart by ANSI-see Reference 1.

Reactor 2, Steam separators 3. Inlet header 4. Main circulation pump 5. Outlet header 6. Pressure suppression pool 7, ECCS vessels 8, ECCS pumps for cooling damaged half of reactor 9. Heat exchangers 10. Clean condensate container 11. ECCS pumps for cooling undamaged half of reactor 12. De-aerator 13. Feed pump,... 

The pressure-suppression type primary containment is a cylindrical concrete structure with an embedded steel liner type with two major compartments a drywell and wetwell. The lower part of wetwell volume is filled with water that works as the condensation pool, and the upper part is a gas compression chamber. The blow-down pipes from the safety relief valves are routed to the pressure suppression pool. 

The elimination of large primary circuit pipes in integral PWRs allows an easing of the containment specification. Pressure suppression systems for PWRs become feasible and several versions have been proposed. 

The pressure suppression function is supported by a four train containment spray system that is continuously in service, with one train supplying spray water from the condensation pool to the gas compression chamber in accident situations the system will start operation at full capacity. Spraying is also possible for the upper drywell - after rerouting, on operator action. The drywell spray is generally initiated only in the event of "small" LOG As to "depressurize" the containment. 

The BWR 90 pressure-suppression containment consists of a cylindrical prestressed concrete structure with an embedded steel liner - as in all previous ABB Atom plants. The containment vessel, including the pressure-suppression system and other internal structural parts as well as the pools above the containment, forms a monolithic unit and is statically free from the surrounding reactor building, except for the common foundation slab. 

A containment is provided that completely encloses the reactor systems, drywell, and suppression chambers. The containment employs the pressure suppression concept. 

Each loop which is open to the containment, contains a drain line to the GDCS pool, and a vent discharge line the end of which is submerged in the pressure suppression pool. 

The PCCS loops are driven by the pressure difference created between the containment drywell and the suppression pool during a LOCA and require no sensing, control, logic or power actuated devices for operation. Together with the pressure suppression containment system, the three PCCS condensers limit containment pressure to less than its design pressure for at least 72 hours after a LOCA without make-up to the IC/PCC pool. 

Design basis Fission product containment Containment vessel passive Pressure suppression type with mmimum penetrations... 

Passive safety injection system reduces core damage probability Pressure suppression containment high retention factor and so limits consequences LOCA (Secondary) Low steam generator secondary side water inventory limits consequences LOCA (Interfacing)... 

Regarding the possible release of radioactive materials and their propagation, there is a series of independent physical barriers fuel matrix, fuel element cladding, leak-tight integral reactor and primary circuit systems, leak-tight containment with the bubbler and pressure suppression system. 

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