U & Pu assay Systems and Expertise

Transcription

1 U & Pu assay Systems and Expertise Dr Patrick Chard Technical Director, Global Measurements & Expertise Tokyo, Thursday September 3rd, 2015 p1

2 Agenda Canberra expertise Staff Experts Research & Development Facilities Radiometric Technology for U & Pu assay Measurement Techniques System Types Integrated Solutions Analysis Tools Measurements & Expertise Services Examples p2

3 CANBERRA at a Glance Worldwide leader in nuclear measurement 50 years in business Approx 1,000 employees 250 customer-facing sales and service personnel 40 PhD s 7 industrial sites 26 sales and service offices 35 distributors Over 5,000 customers Parent company-areva p3

4 CANBERRA Global Team p4

5 CANBERRA Expertise Physicists Software engineers Electrical engineers Design / mechanical engineers Project-oriented multi-disciplinary teams CANBERRA Technology Group: Collect new ideas and roadmap to implement new technology p5

6 CANBERRA radiometrics expertise (1) Recruited from academia, operating nuclear sites, relevant industries Many qualified with radiometrics post-graduate degrees: reactor physics, radiation transport physics, detector physics Links with universities sponsored student projects Physics teams based at Meriden, Harwell, Montigny, Loches 42 field-based staff in Measurements & Expertise group based mostly at customer sites Brings unique field operations experience and site level knowledge Close working relationship between factory and field staff Feedback improves products and field staff can access high level expertise p6

7 CANBERRA radiometrics expertise (2) Members of national and international groups: Standards and best practice committees (e.g. ASTM, NPL) R&D collaborative organisations (e.g. ESARDA, INMM, LANL, ORNL, Universities) Partnership with industry: - Joint projects, - Commercialisation of technology from national institutes and academia LANL (Tomographic Gamma Scanner) CEA (ipix gamma camera ) AREVA (D&D solutions) Liverpool University (special detectors and solutions, radiometric laboratory) p7

8 CANBERRA Facilities Detector manufacture - Meriden, Loches System assembly and testing - Meriden, Harwell, Montigny, Loches Calibration - Characterised Pu, U fissile standards, other gamma / neutron / X-ray sources - Shielded facilities for active testing Research & Development - New detector types (e.g. 3He replacements for Pu/U detection) - Assay algorithms and software - Fundamental physics - Assay procedures - Product evolution p8

9 Agenda Canberra expertise Staff Experts Research & Development Facilities Radiometric Technology for U & Pu assay Measurement Techniques System Types Analysis tools Integrated Solutions Measurements & Expertise Services Examples p9

10 NDA - Applications Three Core Applications Radioactive Waste measurements Process Control Safeguards Radioactive Waste Measurements Waste characterisation Waste Segregation Free Release Material or VLLW from LLW LLW from Pu contaminated waste Accurately Quantify LLW Accurately Quantify Pu / U Contaminated Waste (Alpha Plants) Process Control Systems integrated into facilities to support operations Safeguards Systems Large range of U, Pu sample measurement systems p10

11 NDA Top 10 questions Used to understand customer goals and develop solution. 1. Assay Goal? - Free Release, LLW, ILW, HLW 2. What radionuclides are of interest? 3. What radionuclides may be present? 4. What is the expected range of activity? 5. What is the range of sample size and matrix? 6. What is the required detection level? 7. What are the typical and maximum count times desired? 8. What are the background levels? 9. What are the constraints of the facility? (material handling, floor space, floor loading, power constraints, environmental, access limitations, source handling and license restrictions). 10. Budget? p11

12 MEASUREMENT TYPE DETECT ISOTOPE (Normal conditions) NDA Technology REMARKS Gross Gamma All gammas contribution sum Correlation ratios between different nuclides are required. NEEDS KNOWN FINGERPRINTS Gamma Spectrometry (LRGS, IRGS, HRGS) Passive Neutron Passive Neutron Coincidence Passive Neutron Multiplicity Active Neutron (prompt) Neutron Active (delayed) Photon activation Photo-fission (delayed neutrons measurement) X-Ray Fluorescence / K-edge densitometry 54 Mn, 60 Co, 106 Ru, 125 Sb, 134 Cs, 137 Cs, 144 Ce, 154 Eu, 235 U, 238 U, 239 Pu, 240 Pu, 241 Pu, 241 Am 238 Pu Pu Pu Pu 242 Cm Cm Cm Cf 238 Pu Pu Pu, 242 Cm Cm Cm Cf 238 Pu Pu Pu, 242 Cm Cm Cm Cf 233 U U Pu Pu 235 U U Pu Pu 14 C, 59 Ni, 63 Ni, 93 Zr, 93 Mo, 99 Tc, 129 I, 135 Cs, 151 Sm Contribution of all actinides. Actinides measurement is only possible without fission products presence. Also sees (alpha,n) sources (alpha,n) interference removed. Three measurements allows 3 unknowns to be determined (Pu mass, matrix, alpha/n) Improve accuracy Neutron generator or random neutron source High sensitivity total fissile assay (mg) possible with neutron generator Cf252 shuffler source. Poorer sensitivity (approx 1/10 g fissile) for pure beta elements characterisation (under development CEA). On concrete packages or to determine the actinides mass in presence of Cm and fission products (CEA) U, Pu Useful for small sample analysis, usually for U/Pu ratio and concentration measurements Calorimetry Alpha (e.g. Pu), Beta (e.g. Tritium) Very accurate but very long count ing times p12

13 Gamma versus neutron Gamma Spectrometry Advantages - Identification capability of radionuclides Disadvantages - Most sensitive technique for Pu assay (strong gamma signal 241Am) - High uncertainties for heavy density matrix (heavy metals) Neutron Measurement - Accurate measurements even for high density wastes - Direct assay of FISSILE mass, even in presence of high gamma background, fission products - High impact of light nuclides (H, C, Cl, B, Cd, Gd) and neutron sources (Cm242, Cm244) - Complex and expensive detectors & electronics p13

14 Low Resolution Gamma Spectroscopy Waste Clearance Monitors G35-90 Packet Monitor NaI system for bagged wastes, sensitive, low cost NaI Q2 Drum Monitor 2 large NaI crystals (3x5x16 ) Provides same sensitivity as HPGe Q2 but in 1/10 th the time. For simple waste streams Cronos Contamination Monitor Plastic scintillation system for loose or bagged wastes, sensitive, low cost G35-90 System (NaI) CRONOS-4 (129l) and -11 (325l) (Plastic Scint) WM2750 System (NaI) p14

15 High Resolution Gamma Spectroscopy Waste Assay Systems Q2 Low Level Waste Assay System SGS - Segmented Gamma Scanner TGS - Tomographic Gamma Scanner Gamma-Ray Box Counter More complex and costly than low resolution but superior performance. Results are more defensible where fingerprints are unknown / uncertain p15

16 Q2: Very Low Level Waste Assay System Purpose: Free Release Assay, VLLW, LLW, Pu / LLW waste segregation Ge detectors High Resolution Standard weigh-scale Matrix correction by transmission source or weight correction Optional calibration by ISOCS modelling (no sources needed) Options: Barcode readers, conveyors, automatic operation Performance: Container Size: 55 gal drums. Detection Limit 137 Cs pci/g Bq/g 235 U pci/g Bq/g 239 Pu - 11 nci/g 400 Bq/g Measurement Time: ~ 10 min. p16

17 SGS: Segmented Gamma Scanner Measurement to locate radionuclides Where the quantities are significant and the driver is accuracy, then the SGS should be used. Useful if waste is inhomogeneous (for example layers) p17

18 Key features Single unified stand using just one lift for both detector and Transmission source housing Rotator is built into the stand (up to 200 L) Optional CP-5 electrical cooling Possible to swap detector and transmission source housing Capable of fitting through a double door Movable using a fork lift Only for 55 gallon drum or smaller Highlights Having one combined unit simplifies the manufacturing and results in a lower cost to manufacture. The unified stand also reduces the factory integration time and the on site installation New Modular SGS p18

19 TGS: Tomographic Gamma Scanner Purpose: Waste and Safeguards Measurements for heterogeneous wastes HRGS based radioassay of drums and other containers Initial technology licensed from LANL, Joint developments to improve performance Transmission and Emission Imaging Can visualize what s inside the drum in 3 dimensions Takes the SGS to the next level Improved accuracy for nonhomogeneous samples Large variety of options available p19

20 manual motor Radioactive Waste Measurements LLW, ILW Quantification Box measurement: Typical measurement B25, SLB-2, ISO-Containers, Dump Trucks Performance Container Size: B-25, SWB, others Detection Limit: 0.3 pci/g If homogeneous matrix with < 0.3g/cm3 density Measurement Time: 30 minutes ISOCS modeling To simplify calibrations Optional weigh-cell Optional Transmission sources but limited performance manual p20

21 Neutron Waste Assay Systems WM3100 WDAS WM3112-HENC IWAS Integrated Waste Assay System WCAS Waste Crate Assay System Cf-252 Shuffler Differential Die-Away Combined Passive / Active Neutron Counting Special chamber designs optimised for specific applications Typically more accurate than gamma spectrometry, but generally only used for plutonium and uranium. p21

22 Neutron Measurements - Capabilities Passive Neutron Coincidence Counting (PNCC) gives 240Pueffective mass Combine 240Pueffective with Pu isotopics data (from plant knowledge or measurement) to get total Pu mass Multiplicity counting (count numbers of neutron pairs, triples,.) can improve accuracy Active Neutron Interrogation counting gives total fissile mass (239Pu, 233U, 235U) Combined passive / active systems for U-Pu co-assay p22

23 Drum counters - Neutron Systems Accurately Quantify U, Pu The WM-3100 series includes WDAS, JCC-21S and the HENC. WDAS ( Waste Drum Assay System): Passive neutron drum counters Provide precise and accurate and sensitive assay of Pu content 3 He detectors Up to 200 liter (55gal) Sensitivity - detection levels of <50 mg W.G. Pu Sort between (TRU, PCM) and LLW Coincidence or multiplicity counting Add-A-source option for matrix correction The WM-3100 can be combined with High Resolution Gamma Spectroscopy for Pu Isotopics Analysis (MGA, FRAM) and U-235 WDAS System Mostly based on He-3 detectors. Alternatives being explored p23

24 Passive Neutron Coincidence Counter Waste Drum Assay Systems (WDAS, HENC) Purpose: Waste and Safeguards Measurements Technique: Fertile isotopes (e.g., 240 Pu) are measured via coincidence or multiplicity neutron counting. HENC High Sensitivity chamber Performance Characteristics: Measurement Range: mg - kg 240 Pu MDAs typically less than 100 nci/g (3.7 Bq/g). Almost down to LW PCM / LLW boundary (0.1 GBq/tonne), but not quite! Still not as sensitive as Q2 (gamma) Accuracy far better than gamma techniques for metal wastes, but affected by moderators and neutron poisons HENC p24

25 Passive Neutron Coincidence & Multiplicity Counters Measure spontaneous fission neutrons from the even isotopes of Pu Counters fresh fuel assemblies, samples, waste containers INVS Inventory Sample Coincidence Counter (JCC-12) INVS Inventory Sample Coincidence Counter III (JCC-13/14) HLNC High Level Neutron Coincidence Counter (JCC-31) Flat Squared Counter (JCC-41) UFBR Universal Fast Breeder Subassembly counter (JCC-61/62) Passive Neutron Collar (JCC-71) Applications Plutonium Plutonium with known Cm/Pu ratio MOX with known U/Pu ratio Cm can dominate neutron counts, may need correction PSMC-01 Multiplicity counter Higher efficiency Improved accuracy JCC-31 PNCC p25

26 Active Neutron Systems Shufflers Cf-252 interrogation source Counts induced delayed fission neutrons Used for U-235 or Pu-239 assay when high gamma spectrum background prevents gamma assay Detection levels approx 50 mg 20 minutes counts Differential Die-Away D-D / D-T pulsed neutron generator interrogation source Counts induced prompt fission neutrons Used for low level U-235 and Pu-239 assay and when gamma exposure rates are high or in the presence of other interfering neutron sources. Detection levels of 1 to 10 mg. 200 seconds counts p26

27 Measure induced fission neutrons from U-235 and Pu-239 Common Interrogation Sources Usual sources: Am(Li) Current supply issue current studies for alternatives e.g. Am(Be) Coincidence Counting separates Am(Li) neutrons from fission neutrons. Active Neutron Counters Active Neutron Coincidence Counters Active Well Coincidence Counter JCC51, similar to PNCC but with sources in end-plugs Active Neutron Collar (safeguards) fuel assemblies Applications Uranium MOX with unknown U/Pu ratio Plutonium with unknown Cm/Pu ratio Plutonium with high alpha value Waste packages, fuel residues JCC-51 Active Well p27

28 Neutron Multiplicity Counters Additional measurement data (triples rate) allows the calculation of three unknowns (efficiency, Pu mass, multiplication,,n ratio.) Extends Neutron Coincidence Counting to less well characterized materials Designed for higher neutron detection efficiency, shorter die-away times and lower electronic dead times Efficiency >60%, Die-away <25 µsec Container sizes from ml to >1m 3 High end systems provide more precise and accurate results for a wider range of material types. PSMC-01 Multiplicity p28

29 Combined and mobile assay systems Standard or custom-design to suit each application Neutron and gamma detectors in same chamber OR Separate neutron and gamma chambers but combined results Mobile trailer-mounted systems Integrated into customer s plant Built into cell shielding walls, allows assay of ILW cans with high dose rates up to few Sv/hr. Conveyors, Barcode readers, dose rate sensors PLCs, automated drum sequencing NDA2000 and supervisor software Wrapper software for user interface p29

30 In-cell Remote Handleable ILW system Harwell (neutron and gamma) p30

31 Dounreay shaft and silo p31

32 HKED / XRF for Pu / U assay in small samples p32

33 HKED / XRF for Pu / U assay in small samples p33

34 Pu / U isotopics analysis Expertise in Pu analysis codes (MGA, FRAM) Expert review for anomalous drum assay results Optimisation of Ge detector choice Special Safeguards measurement systems In-built Isotopic analysis in standard waste assay systems Data analysis built-in to standard NDA2000 control software Proven, Assured reliability Integrated with Gamma and Neutron assay results p34

35 Pu / U isotopics analysis Software setup on customer assay systems Canberra expertise as code developers and operators Extensive field experience of performance under challenging conditions (waste, interfering nuclides) Special code (MGAv10) developed for waste assay allowing more robust operation and improved accuracy p35

36 NDA 2000 Performs assays (acquisition and analysis) Control counter hardware directly Handles both gamma and neutron data assay and reporting Routine Operation can be as simple as a single click of a button. p36

37 Agenda Canberra expertise Staff Experts Research & Development Facilities Radiometric Technology for U & Pu assay Measurement Techniques System Types Integrated Solutions Analysis Tools Measurements & Expertise Services Examples p37

38 CANBERRA Offering 1. Consultancy Services for complex systems 2. Method Development 3. Measurement Procedures 4. Onsite measurement services and characterisation reports 5. Assistance to system operations 6. Expert Data Review 7. System Calibration Services p38

39 CANBERRA Mobile Equipment LN2 BEGE ISOCS system CP5 BEGE ISOCS system FALCON 5000 NaI detector / Osprey Inspector 1000/2000 (NaI / LaBr / CZT) N50L neutron slabs ipix Gamma Camera SMOPY Burnup monitor p39

40 Modelling Codes MCNPX Feasibility / Design / calibration of passive / active neutron assay systems (PNCC, PNMC, DDA, AWCC, Cf shuffler) Neutron shielding design Feasibility / Design / Calibration of Gamma Spectroscopy systems p40

41 Modelling Codes ISOCS Calibrate with no need for radionuclide sources Complex geometries! HpGe, NaI, LaBr and CZT Mercurad Doserate calculations Support safety cases for customer projects System design Powerful geometry modelling Dose rate mapping Codes used in combination p41

42 Innovation in Services for Pu / U assay Advanced ISOCS Specialist tool to fit measurement data to uncertain model parameters Improve measurement accuracy (e.g. hotspot unknown location un drum) Reduce waste sentencing costs SMOPY Spent fuel assembly underwater burnup verification (neutron and gamma counting) Potential extension to characterisation of fuel residues (e.g. sludge) p42

43 Agenda Canberra expertise Staff Experts Research & Development Facilities Radiometric Technology for U & Pu assay Measurement Techniques System Types Integrated Solutions Analysis Tools Measurements & Expertise Services Examples p43

44 UF6 Characterisation in Cylinders Successfully developed the physics technique to discriminate between clean and dirty UF6 in storage cylinders Gamma spectroscopy studies to identify signature ISOCS modelling and measurement on test cylinders Provided a platform for future development of a routine high throughput system for stored cylinders p44

45 Counts/MeV/s Consultancy for Sellafield sludge waste Aim to Identify feasible techniques for activity and fissile mass Early discussion with customer team MCNP modelling to predict performance: spectroscopy, active neutron assay Calculate detection limits and feasible waste containment AG 0.2 void fraction: Background spectrum (not scaled) 3.00E E E E E E E E(MeV) p45

46 Decommissioning Scenario : ISOCS Example La Hague Radiological state of glove boxes ISOCS measurements Estimate the Pu isotopic composition and weight (ranging from one gram to over 100 grams) p46

47 La Hague UP /2 Dismantling project of La Hague Reprocessing Plant, UP2-400 unit Lack of knowledge about position, identification and radiological characteristics of residual radioactivity. M&E implemented a full solution including: Definition of dismantling scenarios Precise waste categorization Radioactive discharge optimization Safety analysis (dose rate, criticality ) Guarantee of contractual threshold to decontamination companies p47

48 La Hague UP /2 Challenges : Very large range of dose rates from 100 ngy/h to 100 Gy/h Limited access to measure hot cells Achievements: Measured more than 50 cells with GM and CZT detectors and modeled with MERCURAD Drastically reduced the cost of the dismantling Avoided the opening of the hot cell and cutting the tanks Limited the risks and released a safety analysis report Quick analysis helped optimise rinsing scenario We proved that more than 50% of the tanks could be considered as VLLW. It drastically changed the original decontaminating and dismantling scenario p48

49 Thank You! Questions? p49