EDMS 1296860 v.1 02/07/2013 General trends in ventilation of radiation zones from the viewpoint of public exposure P. Vojtyla / DGS-SEE-XP

Yield per primary proton EDMS 1296860 v.1 02/07/2013 Yield per primary proton

Produced radioactivity EDMS 1296860 v.1 02/07/2013 Produced radioactivity

A closed zone: The worst case for RP EDMS 1296860 v.1 02/07/2013 A closed zone: The worst case for RP

Resulting exposure Annual effective dose E (Sv); EDMS 1296860 v.1 02/07/2013 Resulting exposure Annual effective dose E (Sv); Radio-toxicity mixes the cards further; Radiation type and energy; Physicochemical behaviour; Human metabolism; Half-life; For exposure type resulting in a committed effective dose, short half-life leads to higher activity but the committed dose tends to be smaller with shorter half-life; Topological arrangement and wind patterns; Habits of the local population.

Wind rose (2011, BA4) To find the maximum Will not be straightforward EDMS 1296860 v.1 02/07/2013 Wind rose (2011, BA4) NW boundary of the site To find the maximum Will not be straightforward

Hypothetical house – NW (250 m) EDMS 1296860 v.1 02/07/2013 Hypothetical house – NW (250 m) Short-lived gases: The usual problem

Hypothetical house – W (300 m) EDMS 1296860 v.1 02/07/2013 Hypothetical house – W (300 m)

Hypothetical house – N (450 m) EDMS 1296860 v.1 02/07/2013 Hypothetical house – N (450 m)

Waste dump: In one of the main wind directions but far away (620 m) EDMS 1296860 v.1 02/07/2013 Waste dump: In one of the main wind directions but far away (620 m)

Conclusions (1) Completely isolated zones are difficult to realize; EDMS 1296860 v.1 02/07/2013 Conclusions (1) Completely isolated zones are difficult to realize; Some air extraction is necessary to keep dynamic confinement; The governing dynamics is such that the prevailing part of the exposure is due to short-lived radioactive gases; Namely: 11C (20 min), 13N( 11 min), 15O (2 min), 14O (1.2 min), 41Ar (1.8 h);

EDMS 1296860 v.1 02/07/2013 Conclusions (2) The only way of reducing the activity of the short-lived gases is to delay them before release; The aerosol-bound radioactivity is efficiently retained by aerosol filters – best in a continuous way in a semi-closed system; Attention on condensation water of such closed systems – high tritium concentrations may result; Use an evaporator (PR issue). Experience from CNGS