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PS Ventilation system

Sylwia Wojnarska 20th September 2012. PS Ventilation system. Proton Synchrotron. Whole PS – run mode simulation. Whole PS – boundary conditions. Fresh air system – velocity inlet every second room, pressure outlet every second room. Velocity sets up according to area of splited face.

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PS Ventilation system

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  1. Sylwia Wojnarska 20th September 2012 PS Ventilation system 20th September 2012

  2. Proton Synchrotron 20th September 2012

  3. Whole PS – run mode simulation 20th September 2012

  4. Whole PS – boundary conditions • Fresh air system – velocity inlet every second room, pressure outlet every second room. Velocity sets up according to area of splited face. • Recirculation system – intels and outlets – velocity inlet with set up velocity according to area. 20th September 2012

  5. Results of run mode simulation 20th September 2012

  6. Results – velocity Velocity in whole tunnel in crossection z=0.2m – just above the inlet of recirculation system 20th September 2012

  7. Results – velocity Velocity in whole tunnel in crossection z=1m – in the middle of the magnet 20th September 2012

  8. Results – velocity Velocity in whole tunnel in crossection z=2m – just above the magnet 20th September 2012

  9. Results – velocity Velocity in whole tunnel in crossection z=3m – in the high of inlets and outlets of fresh air system 20th September 2012

  10. Results – velocity Velocity in crossection of room number 1 – in the outlet of fresh air system 20th September 2012

  11. Results – velocity Velocity in crossection of room number 2 – in the inlet of fresh air system 20th September 2012

  12. Results – velocity Velocity in crossection of room number 4 – in the inlet of fresh air system 20th September 2012

  13. Results – velocity Velocity in crossection between room number 3 and room number 4 20th September 2012

  14. Results – velocity Velocity in crossection between room number 7 and room number 8 20th September 2012

  15. Results – velocity Velocity in crossection of central room – inlet of fresh air system 20th September 2012

  16. Results – velocity Voctors in crossection of the room number 1 – outlet of fresh air system 20th September 2012

  17. Results – velocity Voctors in crossection of the room number 8 – inlet of fresh air system 20th September 2012

  18. Results – velocity Voctors in crossection between room number 7 and room numer 8 20th September 2012

  19. Results – velocity Velocity in crossection of the galleries 20th September 2012

  20. Results – pressure Pressure in whole tunnel in crossection z=1m – in the middle of the magnet 20th September 2012

  21. Results – pressure Pressure in whole tunnel in crossection z=2m – just above the magnet 20th September 2012

  22. Results – pressure Pressure in the whole tunnel in crossection z=3m – in the high of inlets and outlets of fresh air system 20th September 2012

  23. Results – pressure Pressure in crossection of room number 1 – outlet of fresh air system 20th September 2012

  24. Results – pressure Pressure in crossection of room number 2 – inlet of fresh air system 20th September 2012

  25. Results – pressure Pressure in crossection of room number 8 – inlet of fresh air system 20th September 2012

  26. Results – pressure Pressure in crossection between room number 2 and room number 3 20th September 2012

  27. Results – pressure Pressure in crossection between room number 7 and room number 8 20th September 2012

  28. Results – pressure Pressure in crossection of central room – inlet of fresh air system 20th September 2012

  29. Activated air in PS tunnel 20th September 2012

  30. Activated air - ingredients Pure air : N,O, Ar and CO2→39 radionuclides withhalf-lives longer than few seconds can be produced. N and O →3H,7Be,10Be,11C,13N, 14O and15O, Carbon-14 40Ar→Argon-41 Whenthe half-life is short, the radionuclide decays beforereaching the ventilation outlet and its activitydecreases (e.g.14O,15O). The nitrogen and oxygenisotopes, 41Ar, Carbon-11(occurs as 11CO and11CO2 )→gaseous form Tritium occurs asHT and HTO. Other radionuclides - 7Be,attach to aerosol particles. Air contains also aerosol particles that can be activated directly→ 24Na and22Na. Radioactiveerosion and corrosion fragmentstransported by the ventilation system→46Sc,48V,54Mn,57Co,58Co and60Co. An advantage of closed air-handling units is thatthey can efficiently decrease the activity of short-lived radioactive gases and other radionuclides (multiplefiltering). 20th September 2012

  31. Activated air – air release from PS tunnel The PS tunnel is not equipped with a directed ventilation system with controlled flow and defined and monitored exhaust stacks. The PS tunnel is not hermetically sealed and the pressure corresponds to the external pressure. The balance of 40 000 m3h-1 of air is therefore displaced from the tunnel into the environment. Air in the PS tunnel is activated by accelerator operation. At a given time t, Aisignifies the rate of activity production. The normal radioactive decaylaw applies to all produced radioisotopes with activity Ai: - change of the radioactivity in time due to decay In every time unit, a portion -dV = V’dt of the total tunnel volume V is displaced into the environment. - change of the radioactivity in time due to volume displacement, with the air exchange rate With these elements, the linear differential equation for the activity present in the tunnel is: Within this model, the activity released into the environment per time unit is: 20th September 2012

  32. Activated air – air release from PS tunnel Radioactive isotopes produced in the PS by activation in air from beam losses. It is assumed that 10 % of the 7.82·1019 protons accelerated in the PS in a yearare lost during extraction at a momentum of p = 14 GeV/c. The loss occurs in an unshielded location of the beam line (as for example the electrostatic septum in SS 31) These release figures are used to calculate the dose to a member of the critical group. The contribution to their annual dose of radioactive air releases from the PS is estimated to be 1.8 μSv (maximum dose is 10μSv). SS 31 – Straight Section between the main magnet units, 31 – number of unit. 20th September 2012

  33. Activated air – air release from PS tunnel Radioactive air releases are grouped in 4 categories: tritium (3H), short-lived gases (11C, 13N, 14,15 O, 18F), aerosol with 7Be and aerosol with beta emitters. There is no directed ventilation in the PS, their concentration is measured at one point in the PS. The activity concentration is then multiplied with the volume of air expelled from the PS by the air-exchange system in order to estimate the radioactive releases. Comparingthe releases estimated in this way with figures calculated according the model above, one finds that the calculation exceeds the measurement by a factor of 5 for short-lived gases and a factor of 10 for 7Be. This result is not surprising, because the smoke tests have shown that the air in the tunnel is not homogeneously mixed. In particular, radioactive air generated in SS 31 will be conducted in the direction opposite to the location of the air monitor. 20th September 2012

  34. Thank you for attention! Any questions? Sylwia Wojnarska 20th September 2012

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