Filtration of air ‒ nuclear installations

Stationary filtration units

Reconstruction of filtration nodes in VVER-type nuclear power plants concerns ventilation systems. All new equipment is designed as connected to the existing equipment of HVAC of safety class 3. Individual systems are also operated in the event of failures (LOCA).
The reason for the reconstructions was to reduce significantly the operation costs of HVAC systems and to increasing the efficiency of radioactive iodine and aerosols capturing. The old filtration systems did not allow efficient measuring of radioactive iodine capture; the latter has been unsatisfactory in terms of environment and nuclear safety. The new CAMFIL filtration devices have eliminated these problems.

Individual filter chambers comprise:
– differential pressure (∆p) measuring on pre-filters and HEPA filters – visual information on clogging of filtration materials;
– check and sampling apertures – sampling of activated carbon (capture of radioactive methyl iodide), sampling of air (radiation control);
– checking mechanisms to measure the filtration cartridges tightness (100% tightness);
– special, built-in flanges for contamination-free (BIBO) replacement of clogged filtration cartridges.

Result and benefits of HVAC system reconstruction:
– operation costs reduction;
– multiple reduction in radioactive waste production (incinerable filter materials);
– aerosols capture efficiency (MPPS) of at least 99.95%, according to EN 1822-1, and radioactive iodine capture filters efficiency of at least 99%; 99%,
– possibility of non-contamination (BIBO) replacement of clogged filter cartridges also during abnormal regimes and emergencies (except for TL12);availability of replacement filtration cartridges and materials;
– immediate maintenance interventions and services;
– ensured fire safety (installation of fire dampers in the HVAC way);
– seismic resistance to Category 1b;
– operation of systems under normal operation, during planned and unplanned outages, in the event of electricity black-out, in emergency modes of refrigerant leakage, severe accident and in the elimination of consequences of the-worst-possible scenario failures;
– 50 years’ service life of both the installation alone and of its main components (excluding filter materials).

MoFi mobile filter units

Mobile device for the local exhaustion of radioactive dust generated by cutting, grinding or burning operations. Depending on the filtration requirements, the individual devices are manufactured in two- or three-stage versions with the possibility to regulate gas/vapour flow rate.

Material: stainless steel.
Aerosols capture efficiency: as required, up to 99.95% (MPPS) according to EN 1822-1.

MoFi comprise:
– differential pressure (∆p) measuring on all filtration stages – visual warning about clogged filtration materials;
– visual “light” alarms in the events of filtration stages clogging and engine failure;
– special, built-in flanges for contamination-free (BIBO) replacement of clogged filtration cartridges;
– frequency converter to set the required desired gas/vapour flow rate.