Habitable system

Because the rate of growth depends, in a complex way, on temperature, supersaturation, size, habit, system turbulence and so on, there is no simple was of expressing the rate of crystal growth, although, under carefully defined conditions, growth may be expressed as an overall mass deposition rate, RG (kg/m2 s), an overall linear growth rate, Gd(= Ad./At) (m/s) or as a mean linear velocity, // (= Ar/At) (m/s). Here d is some characteristic size of the crystal such as the equivalent aperture size, and r is the radius corresponding to the... 

There is no simple or generally accepted method of expressing the rate of growth of a crystal, since it has a complex dependence on temperature, supersaturation, size, habit, system turbulence, and so on. However, for carefully defined conditions crystal growth rates may be expressed as a mass deposition rate Rq (kgm s ), a mean linear velocity v(ms ) or an overall linear growth rate G (ms ). The relationships between these quantities are... 

The Control Room Ventilation and Air Conditioning Systems are designed for uninterrupted safe occupancy of the control room during post accident shutdown in accordance with GDC 2, 4, 5, 19 and 60 (see CESSAR-DC, Section 9.4.1.1). Fire protection for the control room is provided by alarm systems and portable fire extinguishers (see CESSAR-DC, Section 6.4.1). The testing requirements for the Habitability System are identified in CESSAR-DC Sections 6.4.4 and 9.4.1.4. 

Outside air will flow through the filter train to the control room to maintain a positive pressure with respect to the surrounding areas including the outside. Room air temperatures are maintained at habitable levels by internal recirculation cooling. The habitability systems are able to reliably perform their functions during emergency conditions due to the... 

Mineral Formula Type and Habit System Density (g cm" ]... 

Control room habitability system reviews have detected the following problems (1) deficiencies in the maintenance and testing of engineered safety features designed to maintain control room habitability ... 

During the licensing of the Spanish NPPs and in later reviews to update their control room habitability systems, studies and design modifications in the following areas have been required ... 

VES Main Control Room Emergency Habitability System... 

Main control room emergency habitability system air storage cylinders (though these air cylinders are housed in the radiological auxihary building, they are included within the containment/shield building fire area). 

The assessment of the consequential effects of a pipe whip event has been addressed separately under internal flood, water spray, steam leakage, etc. Those systems designated essential for safe shutdown in the event of pipe rupture are the reactor coolant system, the steam generator system, the passive cooling system, the protection and safety monitoring system. Class 1 dc, the uninterruptible power supply, main control room and habitability system, contaimnent penetrations and isolation valves. 

The Main Control Room Emergency Habitability System (VES) / Control Support Area (CSA) are designed so that the occupants of the MCR are protected against external smoke. 

Manual and automatic actuation of the main control room habitability system is achieved via the protection and safety monitoring system. This is described in Section 6.7. 

The main control room habitability system must protect the operators inside the main control room against the release of radioactive material. 

Operation of the main control room habitability system is automatically initiated on high-2 particulate or iodine radioactivity set point, or low pressuriser pressure, a safety related signal is generated to isolate the main control room from the nuclear island non-radioactive ventilation system and to initiate air flow from the main control room habitability system storage tanks. Isolation of the nuclear island non-radioactive ventilation system consists of closing valves in the supply and exhaust ducts that penetrate the main control room pressure boundary. Main control room habitability system airflow is initiated by a signal which opens the isolation valves in the main control room habitability system supply lines (see Section 6.4 of Reference 6.1). 

In order to supply breathable air to the occupants of the main control room, the main control room habitability system is composed of compressed air storage tanks, two air delivery flow paths, associated valves, piping, and corresponding instrumentation. The tanks contain enough breathable air to supply the required air flow to the main control room for at least 72 hours. The main control room habitability system is designed to maintain CO2 concentration less than 0.5% for up to 11 main control room occupants (see Section 6.4.1.1 of Reference 6.1). 

Maintains the main control room emergency habitability system passive cooling heat sink below its initial design ambient air temperature limit. 

Isolates the HVAC penetrations in the main control room boundary on high-high particulate or iodine concentrations in the main control room supply air, or when the pressurizer pressure falls below the low setpoint, or on extended loss of ac power to support operation of the main control room emergency habitability system. 

Main control room emergency habitability system. 

Main control room supply air duct radiation monitors. These monitors measure the concentration of radioactive materials in the air that is supplied to the main control room. The monitors initiate the supplemental air filtration system on high gaseous concentration and to isolate the air intake and exhaust ducts and activate the main control room emergency habitability system on high particulate or iodine concentrations. Alarms are provided in the main control room. 

This subsection should present relevant information on the habitability systems. The habitabiUty systems are the engineered safety features, systems. 

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