Monitoring of Radioactive Air Releases Associated to the PS Operation : What has changed ?

F. Malacrida, J. Regnard and J. Vollaire

PS-LIU 27/05/2014

Outline Context (situation before LS1 and PSRWG

report) What has changed during LS1 (new ventilation

system) New environmental monitoring system Conclusions

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Context (the situation before LS1)

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Some conclusions from the PSRWG reports (2011)

Decision to replace the PS ventilation was driven by the reliability of the AHU (dating from the PS construction)

Collective dose for the project: 13.5 man.mSv(after careful optimization and ALARA committee approval)

GOOD OPPORTUNITY TO IMPROVE THE SITUATION !!!!

PS-LIU 27/05/2014

The Ventilation System (before LS1)

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Recirculation of the air + supply of fresh air (8 x 4000 m3/h)

Tunnel is in overpressure (radioactive air could be measured in accessible areas)

No defined air release points (environmental impact based on air sampled inside the extraction area)

Many known openings….

Context (the situation before LS1)

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B. 353Inputs for the new ventilation design and LS1

Use “clean” air for the center of the ring Air flow from accessible areas to the ring Improve the air tightness of the ring

Detailed RP note from G. Dumont & M. Widorski

140 nSv per hour of stay (280 mSv for 2000 h)

Improvement of the air tightness (examples)

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Thanks to EN-MEF, GS-SE and GS-ASE for the work !

Now

Before

Now Before

NowPS Bridge

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Context (the situation before LS1)

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Site/Facility Station Release (m3) Short Lived (Bq) 7Be (Bq) Alpha (Bq) Beta (Bq) Tritium (Bq) Dose (mSv) Meyrin 9.97E+08 5.22E+13 1.44E+09 6.16E+05 5.08E+07 9.32E+10 8.47

ISOLDE PMV170 7.9E+07 1.16E+13 6.74E+06 6.16E+05 5.47E+05 1.05E+10 3.86 PS Main Ring PMV174 2.8E+08 2.56E+13 9.39E+08 < DL 3.32E+07 9.00E+09 3.06 n-TOF PMV171 5.0E+06 6.86E+12 < DL < DL 1.42E+04 3.45E+09 0.68 TT10 Injection West PMV11 2.9E+08 4.53E+12 2.11E+08 < DL 8.73E+06 1.39E+10 0.41 PS BOOSTER PMV175 2.7E+08 3.04E+12 2.79E+08 < DL 8.30E+06 1.24E+09 0.25 TT70 Transfer PS-SPS PMV173 6.1E+07 5.19E+11 2.51E+04 < DL < DL 5.51E+10 0.17 HIRADMAT PMV70 7.1E+06 1.15E+10 4.24E+03 < DL < DL < DL 0.02

Maximum Dose 8.47

Installed in 2010(sampling in

Septum 16 area)

Summary of recommendations Use fresh/clean air at the center of the ring (B.

353) Provide a permanent air extraction greater

than the fresh air supply. The goal is to achieve a dynamic confinement and a guided air flow from occupied areas toward the ring

Implement defined release points to allow a more realistic monitoring of environmental releases

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Different Release Points

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The Monitoring Stations

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Ventilation Monitoring Station (VMS) Ventilation Gas Monitor Aerosol Sampler Flowmeter

Three inside “bungalows” (outside)

One in Building 151 (with a phonic insulation !)

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Status of work and Budget (as of today) Minor infrastructure work to be completed in

the coming weeks but stations are online (piping insulation, FB locks….)

Annual commitment 205 kCHF. Order this week for two monitoring stations

(~140 kCHF) (as two in stock at CERN were “loaned” for the project and need to be replaced)

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Conclusions Assessment of the situation before LS1 has

allowed to greatly improve the situation regarding air management during PS operation (improvement of dynamic and static confinement)

4 Monitoring stations (and associated infrastructure) were implemented during LS1to allow a more accurate assessment of the PS environmental impact in the future

Situation at workplace will be re-elevated once beams (high intensity / dedicated loss ?) are back

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