Building 6580 Zone 3 Ventilation System

Multi-Zone System - A building heating, ventilation, and/or air conditioning system that distributes conditioned air to individual zones or rooms. 

The makeup-air unit supplying Zone 2 receives its air from the building distribution system, the Zone 3 ventilation system (fan 3), boosted by fan 13 and recirculated by fan 11. The volume of makeup air is determined by the amount of air exhausted from the east and west Zone 2 sections, the amount of makeup air supplied to Zone 2A (which includes the Zone 1 supply air), less the amount of infiltration air into Zone 2. In addition to maintaining the correct pressure differential, the Zone 2 system provides at least four air changes per hour in Zone 2 and provides necessary environmental conditioning. The volume of recirculated air is regulated by a manual intake damper located in the intake duct of the Zone 2 filter and cooling coil. 

Zone 2 air (supplied by the Zone 3 ventilation system) is cooled by the existing building air chiller and preheated if necessary by a hot-water coil in the system. The temperature of Zone 2 is controlled by a thermostat located in Room 107. This thermostat controls the cooling coil... 

A TSR requirement to verify that Zone 1 and Zone 2A ventilation exhaust HEPA and charcoal filters are in-service vwll be implemented to assure that exhaust gases are being filtered when the HCF ventilation system is in operation. A TSR requirement to verify the ventilation system fan sequencing interlock is operable vvnil be implemented to ensure that proper building airflow patterns are maintained in the event of exhaust fan failures. The ventilation system exhaust ducting provides only an inherent passive safety function (i.e., confinement) and no specific TSR controls are required to ensure continued performance of this function. 

The ventilation system for Zone I In the lO -N Building where there Is potential for high air contamination levels Is highly reliable Normal ventilation of this zone could be maintained even though there was a failure of the normal supply fan, one of tvo normal exhaust fans and one source of power. At the other extreme, ventilation systems for Zones which serve no confinement function have no spare fans and are supplied with only one source of power. 

A . l ventilation air to the 105-N Building except for the control room is supplied by blowers In a fan room to the left and front of the reactor. The air ventilation system is zoned as described In Section 7 of Volume 1. 

The Savannah River Site (SRS) reactors are designed with an airborne activity confinement system (AACS) rather than a containment system. The AACS is an active ventilation system that continuously exhausts air from prescribed zones in the reactor building through a set of filters in order to prevent unattenuated release of contaminated air to the environment under accident conditions. The system is designed such that air flows from areas of least expected radioactive contamination to areas of higher potential for radioactive contamination. This is achieved by maintaining the process areas at negative pressures by the operation of fans and dampers. 

In all the zones in both the buildings, it is seen that the build-up of TVOC levels during system shut-down periods are quite low and the introduction of ventilation is often able to dilute the TVOC levels to a reasonably acceptable level. 

This hierarchical structure provides the foundation for information access that is, the information search capabilities that enable rapid access of, say, the calibration records for the Heating, Ventilation, and Air Conditioning (HVAC) system controlling zone 1 within the biochemistry building. 

In a center aisle system, the cooling towers are not used for ventilation. Instead, fans located at the center of the building are employed. Air is drawn fix>m the sides of the building, and flows across the cells towards the central exhaust point (Figure 3). This system improves conditions over the cells, by providing a horizontal exhaust flow, which reduces acid contamination above the cells. This horizontal flow pattern provides an acceptably low level acid concentration at the worker-breathing zone (typically defined as 1.5 m above the cathodes). 

Fire (radiological and toxic material) Forklift fire incident causes transfer cask breach with possible target exposure and airborne release Failure of electrical equipment or system in SCBs, SGB, ventilation hood, Zone 2 or Zone 2A canyon Lightning strike External fire (vehicle accident, aircraft crash, other building fire) irradiated isotope production target, up to 20,000 curies. Volatiles in process cold traps, up to 70,000 curies. Same material as toxic spill. Residual radiological contamination. 

Building 6580 house-air supply fen 3 (Provides conditioned ventilation air supply to the HCF through Zone 2 fan 13.) Shutdown due to loss of electrical power or fan electrical failure Onsite or offeite electrical or mechanical malfunction Control and monitoring system indications and periodic maintenance inspections None Loss of conditioned intake air (less than 6 air changes per hour)... 

Floor plans of various buildings have been optimized based on the equipment and systems within, on functional needs, space utilization, radiation zoning, accessibility, serviceability, maintenance, transportation and ventilation aspects, and on access philosophy. 

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