Information session on aircrew exposure to cosmic radiation – Brussels – 20/01/2009

S. Pepin (Federal Agency for Nuclear Control)

Belgian regulations with respect to cosmic rays exposure and results of the dose assessment

What is cosmic radiation ? Primary cosmic radiation: high energetic particles from space (mainly hydrogen and helium nuclei)

Galactic component (main component): e.g. supernova explosions,…

Solary component (11-years cycle, may be significant in case of solar disturbance event / solar flare – e.g. 1956)

What is cosmic radiation ?

Secondary cosmic radiation - interaction of primary cosmic radiation with earth’s atmosphere => secondary particles

2 main factors affecting the flux of cosmic radiation:

- Altitude (absorption by the atmosphere)

- Latitude (protection due to earth’s magnetic field decreases with latitude – highest dose near the poles)

European regulatory framework (1)

European Directive 96/29/EURATOM

If dose > 1 mSv/y, airlines shall:

• assess the exposure of the crew concerned • take into account exposure when organizing working

schedules with a view to reducing the doses of highly exposed aircrew.

• inform the concerned workers about the health risks their work involves.

• take care of limitation of doses during pregnancy (< 1 mSv/y + ALARA - “As Low As Reasonably Achievable”).

European regulatory framework (2)

Radiation protection 88: “Recommendations for the implementation of Title VII of the European Basic Safety Standards Directive concerning significant increase in exposure

due to natural radiation sources”

- “Highly exposed aircrew” : > 6 mSv/y- 1 – 6 mSv/y: individual estimates of the dose- > 6 mSv/y: appropriate medical surveillance

Belgian regulatory framework (1)

Euratom directive => Royal Decree of 07/20/2001 (article 4 and 9)

Art. 9 : For aircrew with dose possibly > 1mSv/y:• assess individual doses • take into account dose assessments in the working schedules

(at least < 6 mSv/y)• inform the concerned workers (+ company medical officer)• limitation of doses during pregnancy (As Low As Reasonably

Achievable – in any case < 1 mSv/y)

NB: till now, no specific medical follow-up if dose < 6 mSv/y

Belgian regulatory framework (2)

- Guidelines from the FANC(http://www.fanc.be => folder “Natural radiation”) - “Exemption criteria” (e.g. altitude < 6000m +

flying time < 700 h)

- If no exemption software-based evaluation

- Yearly dose evaluation if dose > 1 mSv/y- Monthly if dose > 6 mSv/y

Results of dose assessment 9 commercial airlines investigated.

Last december, information campaign for non-commercial airlines

Commercial airlines:- 3 “exempted” (“air taxi” companies)- 6 with doses > 1 mSv/y

Software used: CARI, IASON-FREE, PCAIRE, GlobaLog

Dose assessment for 1429 persons

907 people > 1 mSv/y (average dose ~ 2 mSv/y)Nobody > 6 mSv/y

Maximal dose = 4 mSv/y

Dose distribution (1)

Company A (IASON), Company B (PCAIRE) – charters flight

Company A

0

10

20

30

40

50

60

70

80

90

1 - 1,5 mSv

1,5 - 2 mSv

2 - 2,5 mSv

2,5 - 3 mSv

Company B

0

20

40

60

80

100

1 - 1,5 mSv

1,5 - 2 mSv

2 - 2,5 mSv

2,5 - 3 mSv

3 - 3,5 mSv

3,5 - 4 mSv

Distribution pattern depends on specific airline (flight profile,…)

Dose distribution (2)

Global dose distribution for all companies

All companies

1,5 - 2

2 - 2,5

2,5 - 3

3,5 - 4

1 - 1,5

3 - 3,5

0

50

100

150

200

250

Dose (mSv)

Nu

mb

er o

f p

erso

ns

Significant # people in the upper range of the distribution

Conclusions - Majority of aircrew members > 1 mSv/y- Dose distribution pattern depends on specific airline

Open issues :- Parameters affecting the dose distribution ? - Which optimisation measures ? - Necessity and type of medical follow-up for dose 1 – 6 mSv/y ?