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1 Radiological protection, dosimetry & environmental monitoring National Training Course on Radiopharmacy, Radiochemistry and Radioisotope Production Site.

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Presentation on theme: "1 Radiological protection, dosimetry & environmental monitoring National Training Course on Radiopharmacy, Radiochemistry and Radioisotope Production Site."— Presentation transcript:

1 1 Radiological protection, dosimetry & environmental monitoring National Training Course on Radiopharmacy, Radiochemistry and Radioisotope Production Site Management Dr. Radu Vasilache Canberra Packard

2 IAEA TC project ROM/6/017 2 Overview 1. Quantities and standards 2. What to survey? Pathways of exposure 3. Radiation protection planning 4. Specific instruments and methods for radiation monitoring 5. Conclusions

3 IAEA TC project ROM/6/017 3 Standards and regulations  Law 11/1996 & Basic Radiological Protection Norms  Set up the dose limits for exposed personnel (20 mSv/year) and population (1 mSv/year)  IAEA Basic Safety Standards

4 IAEA TC project ROM/6/017 4 Quantities to be measured / calculated  Doses:  Absorbed dose D = dE/dm, measured in Gy (1 Gy = 1 J/kg)  Equivalent doses (used in practice for external radiation, measured): Personal equivalent dose (penetrating) H p (10), measured in Sv (1 Sv = 1 Gy for photons), for personnel monitoring Ambient equivalent dose H*(10), measured in Sv, for area monitoring  Effective committed doses (used in practice for internal exposure, calculated): the dose that an individual will receive over a number of year, resulting from the intake of radiaoctive substances

5 IAEA TC project ROM/6/017 5 Quantities to be measured  Activity (measured in Bq):  External contamination of equipment & personnel  Internal contamination (WBC)  Effluents (gaseous & liquid)  Waste

6 IAEA TC project ROM/6/017 6 Radiation protection planing Steps for building up a proper RP management plan: 1. Identify all possible pathways / sources of exposure specific to the site (e.g.: external exposure at the cyclotron site, in the hot-rooms, etc., internal exposure possibilities, ways of discharging effluents, etc.) 2. Identify all possible accidents via a fail chart, set up emergency response plan 3. Identify points of continuous monitoring and what needs monitored

7 IAEA TC project ROM/6/017 7 What to survey? Survey targets in a cyclotron production site & paths of exposure:  Protection of the working personnel:  Direct exposure to external radiation – dose monitoring  Internal exposure through inhalation & ingestion – internal contamination (activity) monitoring, doses are calculated  External contamination  Protection of the public  Gaseous effluents  Liquid effluents  Waste disposal

8 IAEA TC project ROM/6/017 8 Dosimetry – personnel monitoring  Quantities to be measured:  H p (10) – personal equivalent dose, penetrating: doses due to external penetrating radiation (above 60 keV), the point of interest is considered as 10 mm below the surface of the skin  H p (0.07) – personal dose equivalent, superficial: doses to to low energy external radiation (photons below 60 keV, beta radiation)  Instruments:  Electronic alarm dosemeters  Film dosemeters  TLDs  Glass dosemeters

9 IAEA TC project ROM/6/017 9 Examples of personnel dosemeters

10 IAEA TC project ROM/6/ Personnel dosimetry – internal contamination  Whole Body Counting  Spectroscopic measurement of intake  Measures the activity and calculates committed dose per radionuclide  Adds up to the external dose

11 IAEA TC project ROM/6/ Personnel contamination

12 IAEA TC project ROM/6/ Dosimetry – area monitoring  Ambient equivalent dose H*(10)  Measured directly, usualy the dose, time stamp and location are logged in  Usually applies to photons (gamma & X) and neutrons  Area monitoring normally involves network monitoring, with detectors sending remotely the data, combined with periodic surveys performed by operators

13 IAEA TC project ROM/6/ Dosimetry for area monitoring - examples

14 IAEA TC project ROM/6/ Area monitoring – hand held units

15 IAEA TC project ROM/6/ Details to be observed  Dose ranges: in areas where the dose rate could have significant fluctuations, a matter of concern should be the saturation of the probes  TTC methods is the answer

16 IAEA TC project ROM/6/ Time – to – count principle Conventional GM Tube Operation TIME PULSE DISCR. WAVE FORMS +HV BIAS

17 IAEA TC project ROM/6/ Time – to – count principle “Time to Count” Operation HV 2 t on t off GM TUBE WAVEFORMS TIME Time Totalizer Pulse Totalizer ÷ Average Time to Count RATE = K TIME TO COUNT

18 IAEA TC project ROM/6/ Time – to – count principle “Time to Count” Behaviour HV +HV 2 SHORT TIME 2 mSec. TIME HIGH FIELD HV +HV 2LONG TIME 2 mSec. TIME LOW FIELD

19 IAEA TC project ROM/6/ Effluent & waste monitoring  Should be integrated in the same RMS software as the dose area monitoring  Involves gas & liquid discharges  Waste (solid & liquid) are to be measured and categorised according to the activity  Can be done via radiometric and / or spectrometric measurements  The architectures of GEM & LEM are similar

20 IAEA TC project ROM/6/ Gaseous and liquid effluent monitors

21 IAEA TC project ROM/6/ Gaseous Effluent Monitor SPING CP/GNS/SCN-1  Two monitors (reactor hall and stack), with 3 channels each – MGN (noble gas), MIR (iodine), MAR (aerosol)  Each channel has a NaI 3x3 inch with UniSpec (can be replaced with any other combination of detector & MCA)  New architectures can combine stabilised NaI or LaBr with Osprey, or HPGe coaxial detectors with electrical cooling and Lynx MCA, thus making totally useless the usage of local computing stations  Result of the combined work of CPRO, GNS and SCN Pitesti

22 IAEA TC project ROM/6/ Gaseous effluent monitor (cont.)

23 IAEA TC project ROM/6/ Control software

24 IAEA TC project ROM/6/ Gaseous effluent monitors – non spectrometric

25 IAEA TC project ROM/6/ Liquid effluent monitors  On-line / in-line

26 IAEA TC project ROM/6/ Waste assay & objects contamination monitors  Radiometric / spectrometric

27 IAEA TC project ROM/6/ Conclusions  From the point of view of the radiological protection, one must observe the following in the site planing:  Plan for the possible incidents and the pathways of exposure  Insure proper monitoring of personnel exposure / contamination  Monitor the environmental releases and keep them under control (limit population exposure)  Monitor waste production  Decide for the best technological solution applicable to the site to achieve the above objectives

28 IAEA TC project ROM/6/ Mulumesc! Întrebări?


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