Fusion Programme - ENEA - Fusione

Fusion ProgrammeTritium roomTritium G.B.S-ADS(recycle)S VDS(oncethrough)N VDS-1(oncethrough)Exhaust ventilationFig. 3.50 - Block diagram of scrubber systemFig. 3.49 - Block diagram ofdetritiation system in ITERtritium plant3000 mm3000 mm 3000 mm 3000 mm4000 mmExhaustventilation1 st Stage 2 nd Stage 3 rd Stage 4 th Stageto STACKwaterPump Pump Pump Pumpto WDSTANK2007 Progress Reportunacceptable releases to the environment during a first transient. In addition, according the presentdesign solutions, the reliability of the normal VDS (N-VDS) and S-VDS to intervene on demand and tocorrectly mitigate in time a large accidental tritium release in the operating area seems low.• An alternative approach to detritiation of the operating areas is proposed as a conceptual design. Theconcept consists of a scrubber (fig. 3.50) capable of contacting, by a spray of water, all the air effluentfrom areas potentially contaminated by tritium. If a tritium spill should occur inside a process room, thecontaminated air channelled into the scrubber comes into contact with the scrubbing water and will loseby dilution the concentration of HTO. The effluents released to the environment should be practicallycleared of HTO.• For fires, it is necessary to assess the behaviour of some critical components, such as filters andrecombiners, which are required to process the fumes produced by combustion (in terms of dusts andvolatile products capable of poisoning the catalyst). Another concern is related to the capability of theventilation systems to maintain, also in the case of fires, a slight de-pressurisation of internal rooms withrespect to the environment in order to avoid an increase in room leaks.• No relevant concerns are related to the capability ofsafely dealing with tornado events.70[3.34] A. Natalizio, M.T. Porfiri, ALARA evaluation for ITERdesign change requests 3 to 65, ENEA Internal