Applicazioni nucleari per il monitoraggio dei rifiuti radioattivi. Incontro Nazionale di Fisica Nucleare 2014

Transcript

1 Applicazioni nucleari per il monitoraggio dei rifiuti radioattivi P.Finocchiaro! Incontro Nazionale di Fisica Nucleare 2014 P.Finocchiaro 1

2 Radwaste production nuclear power plants fission residues activated materials spent fuel radwaste drums water pool storage site casks geological repository P.Finocchiaro 2

3 Radwaste production mining production of radiotracers industry diagnostics therapy storage site P.Finocchiaro 3

4 Radwaste production mining industry fuel weapons! waste waste P.Finocchiaro 4

5 Waste??? New Old e-waste Old New Old? Radwaste Old? What Next? P.Finocchiaro 5

6 IAEA 2012 existing radwaste worldwide Storage Disposal total of > 30 million m 3 equivalent to (1 km) x (1 km) x (30 m)! P.Finocchiaro 6

7 radwaste storage sites in Europe temporary centralized repositories surface repositories cave repositories geological repositories under development/authorization in operation closed P.Finocchiaro 7

8 Rad(waste) monitoring: a few INFN activities DMNR HELNEM RADSIEVE P.Finocchiaro 8

9 DMNR LNS Detector Mesh for Nuclear Repositories! Real-time online monitoring of radioactive waste! local! data! storage! Data! wireless! network! wired! network! remote! data! storage! Web! P.Finocchiaro 9

10 radwaste produced worldwide usually packed into special drums the storage site should be monitored for leaks or breaks, to prevent possible contamination of the environment and/or people online monitoring can minimize the need of human intervention inside (ALARA) No repository with online real-time monitoring (to our knowledge)! P.Finocchiaro 10

11 On-line monitoring of short/medium term radioactive waste storage Application of non-conventional detectors for decommissioning DMNR: goals real-time continuous activity monitoring & recording on-line availability of data to control authorities, fire departments, local and national governments, etc. radwaste handling by means of advanced tools and procedures suitable for reducing the risks to the local workers and to the population P.Finocchiaro 11

12 They know, they know, but... I ll tell them anyhow!!! basic radioactivity coming out is gamma rays beta particles are mostly stopped inside the material and in air I love fuel rods alpha particles are immediately stopped inside the material fission fragments are immediately stopped inside the material neutrons (from fission) come out very easily but at very small dose. The amount of fissile material in the drums is small: it is removed before packing the drums (not so for spent fuel rods) gamma rays are penetrating, therefore they come out easily and abundantly P.Finocchiaro 12

13 if I want to prevent my house from being flooded what should I check? 1) I could monitor the faucets and drains (i.e. possible sources of water leaks) 2) I could monitor the presence of water in my bedroom or in my shoes faucets drains bedroom shoes So far, most efforts are directed toward 2 we trust the exponential decay law of radioactivity P.Finocchiaro 13

14 we (scientists) trust the exponential decay law of radioactivity what about laypersons? environmentalists? total of 435 reactors in the world! sooner or later decommissioning will take place temporary and permanent storage required N! where? acceptability for populations? age [years]! we proposed to set-up a system for in-place storage monitoring P.Finocchiaro 14

15 6! 7! 5! 8! SiPM 1! 2! 3! 4! 9! 10! 11! 12! each peak corresponds to a discrete number of detected photons! low bias voltage (30V) high gain 1 photon gives rise to a signal of about 10^6 electrons SiPM fiber SiPM SciFi! Radiation! SiPM! SiPM! P.Finocchiaro 15

16 gamma source! 2.7MBq at 10cm! background! background! 3D reconstruction by crossed fibers! X! P.Finocchiaro 16

17 international limit for nuclear workers! household Radon! strong source employed:! dose at 1m msv/h! P.Finocchiaro 17

18 µsl! tests with 241 Am, 22 Na, 137 Cs, 60 Co sources! µsb! P.Finocchiaro 18

19 test with real radwaste drums! temporary storage inside the former power plant of Garigliano at Sessa Aurunca (SOGIN S.p.a.)! 4 sensors (+geiger) on a pushcart! placed at 7 positions (P0-P6)! with increasing dose rates! test start:! posizions P0 P6! 24h long test in P6! P.Finocchiaro 19

20 Technology transfer! collaboration agreement! INFN - SOGIN! signed on 8-Nov-2012! duration: 2 years! implementation of a prototype DMNR monitoring system in a new radwaste repository (Garigliano former power plant)! P.Finocchiaro 20

21 Front-end and data acquisition scheme local Data Base Discr! Discr! Coinc! unique ID! LAN! wireless WAN remote Data Base counters! WEB Discr! Coinc! control authorities Discr! unique ID! population organizations IAEA waste drum units! FPGA data acquisition! and control! local wireless and LAN! global WAN! P.Finocchiaro 21

22 user interface online display and data check" counting rate channel by channel" programmable alarm levels" details available in real time" down to the single drum and to" the single fiber around a drum" direct connection to the sensor database! 3D virtual navigation tool electronics and computing entirely developed at LNS P.Finocchiaro 22

23 new system: patent in preparation! INFN SOGIN Ansaldo Nucleare P.Finocchiaro 23

24 HELNEM LNS Collaboration with JRC & Euratom: neutron detection out-of-core monitoring in NPP why neutrons?! spent fuel monitoring in place and/or during transportation Plutonium, I love you... preventing the smuggling of nuclear fuel detection of possible diversion of fuel elements from Castor containers (P.Peerani, M.Galletta, Nuclear Engineering and Design 237 (2007) 94-99)! P.Finocchiaro 24

25 ensuring continuity of knowledge current monitoring method: video camera our idea: granular, real time, automatic P.Finocchiaro 25

26 How? materials for thermal neutron conversion: 3 He n 3 He 3 H p!(0.025)! 5330 b! available energy 0.76 MeV no gamma rays perfect gas detector but... worldwide lack of 3 He P.Finocchiaro 26

27 materials for thermal neutron conversion: which one? 6 Li!!(0.025)! 940 b! available E 4.78 MeV 157 Gd!!(0.025)! 240 kb! 113 Cd!!(0.025)! 20 kb! 10 B!!(0.025)! 3840 b! available E 2.79 MeV (and gamma rays) large available E but in form of gamma rays: difficult neutron identification P.Finocchiaro 27

28 neutron converter production 6 LiF Si detector P.Finocchiaro 28

29 Si detector + 6 LiF 4 He! 6 Li! n! 7 Li! 6 LiF converter 3 H! Silicon detector Triton detected Alpha detected 4 He! 6 LiF converter 7 Li! 6 Li! n! 3 H! 2 converters: double efficiency P.Finocchiaro 29

30 AmBe neutron source 1.6E6 n/s thermal flux! 150 n/s/cm 2 Si + 6 LiF neutron source PET moderator expected! 4 cps measured 3.3 P.Finocchiaro 30

31 features next steps 6 Li deposits over large area (A4?) better efficiency (up to 50%?) scintillators... P.Finocchiaro 31

32 test with AmBe source: Scintillators + 6 LiF alpha + gamma tritium " neutrons alpha + gamma good intrinsic efficiency position sensitive ( x! 1-2 mm) low cost many possible geometries and schemes tritium " neutrons...and more to come RM2013A LiF converter P.Finocchiaro 32

33 real-time castor storage monitoring P.Finocchiaro 33

34 Ongoing collaboration with JRC & Euratom: large panels for neutron coincidence measurements as possible 3 He panels replacement 3 H, 4 He Collaboration with CIVIDEC (Austria) gamma diamond detectors for thermal neutrons outstanding results with the first test at a reactor CIVIDEC will purchase our neutron converters P.Finocchiaro 34

35 RadSieve LNS in collaboration with JRC Ispra Sorting table for hot spots detection in decommissioning can be used for scrap metal as well P.Finocchiaro 35

36 Final summary Radwaste is a problem, will become a priority in the forthcoming years INFN has started to contribute to this field Ultra-high-tech is not required, recycling our know-how is already a good goal The society needs our support, we should not be blind or snobby Ivory Tower Technology transfer is a relevant issue that we need to strenghten P.Finocchiaro 36

37 PS: last minute news (Friday 21-Mar) In spite of decades of neverending discussions and nominations our management should pehaps signal that INFN is DOING P.Finocchiaro 37

38 credits...and all the others I am forgetting P.Finocchiaro 38