Gaseous Radwaste System

The APIOOO gaseous radwaste system is a once-through ambient temperature activated earbon delay system that collects and processes gaseous wastes originating from the reactor coolant system that are radioactive, to prevent an imcontrolled atmospheric release. The system includes a gas cooler, a moisture separator, an activated carbon-filled guard bed and two activated carbon-filled delay beds. Also included in the system are an oxygen analyser and a gas sampler. 

The following design requirements for the gaseous radwaste system support safe operation of the plant under normal operations ... 

The gaseous radwaste system must have the capacity to process the maximum anticipated flow of hydrogen and nitrogen containing trace amounts of radioactive gas arising from the normal primary coolant letdown operations and from the reactor coolant drain tank. 

The levels of radiation released from the gaseous radwaste system must be within the speeified limits. 

The gas leaving the delay beds must be monitored for temperature, flow rate and radioactivity, alarmed should an abnormal condition requiring attention occur, and the diseharge line closed on radioactivity in the gaseous radwaste system in excess of a predetermined set point or low ventilation exhaust duct flow. 

The gaseous radwaste system is designed to accept the following expected inputs, as described in Section 11.3.1.2.1.1 of Reference 6.1 ... 

Use simplified radwaste systems based on an ion exchange process for the liquid radwaste system and a charcoal bed system for the gaseous radwaste system ... 

Primary containment is provided by the vessels and pipework of the treatment system. The system is designed to operate at pressures only slightly above atmospheric this minimises the rate of loss in the event of a leak. Secondary containment is provided by the building stmcture of the Nuclear Island. The gaseous radwaste system will be located internally, with no points where there could be leakage directly to external environment. Further details of the system are provided in the Environment Report (Section 3.3), and the EDCD section 11.3, (Reference 14.2). 

Management systems and process will be developed during the site licence application phase (as described in Chapter 9 of the PCSR). This will include systems and process relating to the operation of the gaseous radwaste system, including monitoring its integrity. 

The input to and outlet from the gaseous radwaste system will be monitored, as outlined in UKP-GW-GL029 (Reference 14.14). Any leakage Ifom the gaseous radwaste system would be detected... 

Gaseous Radioactive Wastes - the Environment Report, section 3.2 of the Environment Report (reference 15.6) summarises the sources of gaseous radioactive waste, the gaseous radwaste system (WGS), and a BAT assessment for the chosen design options. 

The gaseous radwaste system, which is described in detail in Reference 15.4, Section 11.3 and summarised in the Environment Report, is designed to work on an intermittent basis as gaseous waste arises from plant operations. 

The radioactive inputs to the liquid, gaseous, and solid radwaste systems are covered in Chapter 11 of the EDCD (Reference 12.1). 

Shielding is provided in the auxiliary building for potentially high radioactivity in the liquid radwaste, gaseous radwaste, and spent resin handing systems. 

The APIOOO radioactive waste (radwaste) management systems control the handling and treatment of liquid, gaseous, and solid radwaste produced within the Nuclear Island ... 

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