1. EVIDOS: Optimisation of Individual Monitoring in Mixed Neutron/Photon Fields at Workplaces of the Nuclear Fuel Cycle EVIDOS: Optimisation of Individual Monitoring in Mixed Neutron/Photon Fields at Workplaces of the Nuclear Fuel Cycle M. Luszik-Bhadra, M. Reginatto, H. Schuhmacher PTB V. Lacoste, Th. Lahaye, H. Muller IRSN M. Boschung, A. Fiechtner PSI M. Coeck, F. Vanhavere SCK-CEN G. Curzio, F d’Errico DIMNP J.-E. Kyllönen, L. Lindborg SSI C. Molinos, R. Tanner NRPB D. Derdau KKK

2. Evaluation of Individual Dosimetry in Mixed Neutron and Photon Radiation Fields Nov. 2001 - April 2005 Evaluation of Individual Dosimetry in Mixed Neutron and Photon Radiation Fields Nov. 2001 - April 2005 Selection of workplace fields Dosemeters and spectrometers used Accompanying calculations Results in workplace fields www.eurados.org/evidos

3. M.Luszik-Bhadra, PTB 6.52 3 Selection of workplace fields C0Canel and Sigma simulated workplace neutron fields Cadarache, FranceOctober/November 2002 C1BWR Krümmel Krümmel, GermanyApril 2003 C2Venus Research Reactor, SCK-CEN and Nuclear Fuel Facility Belgonucléaire Mol, BelgiumJune 2003 C3PWR Ringhalsverket Ringhals, Swedenplanned for fall 2004 C4Fuel processing plant / Magnox Reactor Sellafield, U.K.planned for spring 2005

4. M.Luszik-Bhadra, PTB 6.52 4 Dosemeters and Spectrometers used  Bonner sphere spectrometer (IRSN)  Directional spectrometers (PTB, DIMNP)  Electronic personal dosemeters  Passive dosemeters and local device  Ambient dose equivalent meters  New area monitors

5. M.Luszik-Bhadra, PTB 6.52 5 Reference Spectrometer Bonner-sphere reference spectrometer set of PE moderators central 3 He proportional counters E n thermal to 20 MeV

6. M.Luszik-Bhadra, PTB 6.52 6 Si-diode Dir./Energy Spectrometer 6 detector capsules on a PE sphere each containing 4 silicon detectors with different converters/absorbers pulse height analysis of detector signals response of each detector depends on energy and direction of incidence unfolding procedures to derive fluence as function of energy and direction

7. M.Luszik-Bhadra, PTB 6.52 7 SDD Direction/Energy Spectrometer Telescope design superheated drop detector (SDD) spectrometer in the centre of a nylon sphere opening viewing 1/6 steradian counting acoustic signals of the detector for selected orientations of the sphere changing the temperature of the SDD, repeating step above unfolding procedures to derive fluence as function of energy and direction

8. M.Luszik-Bhadra, PTB 6.52 8 Active Personal dosemeters Siemens EPD-N2 (n,  ) Siemens EPD-N (n th,  ) Aloka (n) Saphydose-n (n) PTB DOS-2002 (n,  ) DIS-N (n,  )

9. M.Luszik-Bhadra, PTB 6.52 9 New Area Monitors New moderator-type area monitor hybrid system central 3 He proportional counter 6 silicon detectors below the surface in different directions SIEVERT instrument Low-pressure proportional counters: tissue-equivalent and graphite walls variance method

10. M.Luszik-Bhadra, PTB 6.52 10 Accompanying calculations  MCNP calculations for simulated workplace fields (IRSN)  MCNP calculations for the VENUS research reactor (SCK-CEN)  Development of unfolding codes for the directional spectrometers (PTB)  Calculation of conversion coefficients Hp(10) >75° (PTB)  MCNP calculations / unfolding for response determination of dosemeters

11. M.Luszik-Bhadra, PTB 6.52 11 The CANEL facility Simulated work place field accelerator-produced 3.3 MeV neutrons D(d,n) reaction 238 U converter produces fission neutrons simulation of shielding by parts from iron, water and polyethylene Broad energy distribution typical for work places (CH 2 ) n duct 238 U shell Iron shell Water lens

12. M.Luszik-Bhadra, PTB 6.52 12 The SIGMA facility Irradiation Chamber 241 AmBe Calibration point The neutrons of 241 Am sources are moderated inside a graphite block

13. M.Luszik-Bhadra, PTB 6.52 13 Spectral distribution of neutrons H*(10) = 143.6± 5.1  Sv/h Hp(10,0 ) = 149.4± 15  Sv/h H*(10) = 122.3± 6.1 pSv.p -1 Hp(10,0) = 126.5± 13 pSv.p -1 SIGMA CANEL

14. M.Luszik-Bhadra, PTB 6.52 14 Directional distribution of neutrons at CANEL MCNP calculation Comparison with results of the directional spectrometer with silicon diodes

15. M.Luszik-Bhadra, PTB 6.52 15 Results of personal dosemeters

16. M.Luszik-Bhadra, PTB 6.52 16 Results of area monitors

17. M.Luszik-Bhadra, PTB 6.52 17 BWR Krümmel

18. M.Luszik-Bhadra, PTB 6.52 18 NTL 11 cask at Krümmel

19. M.Luszik-Bhadra, PTB 6.52 19 Spectral distribution of neutrons Full lines: Unfolding results of Bonner spheres Dotted lines: Unfolding results of the directional spectrometer (Maxed)

20. M.Luszik-Bhadra, PTB 6.52 20 Preliminary H*(10) and H p (10) values

21. M.Luszik-Bhadra, PTB 6.52 21 Results of personal dosemeters

22. M.Luszik-Bhadra, PTB 6.52 22 Results of area monitors

23. M.Luszik-Bhadra, PTB 6.52 23 SUMMARY AND OUTLOOK  Measurements were performed at 2 simulated and 10 real workplace fields  Results measured at 6 places are shown  Complex analysis of energy and directional distribution of neutrons  Several personal dosemeters show over-responses in reactor fields  Further analysis of the directional distrution of neutrons  Further consistency checks with dosemeter responses  Further Presentations at SSD14 and IM 2005