Monitoring and Measurement Approaches. P. Schmidt, Wismut GmbH Chemnitz, Germany Head of Department of Env. Monitoring and Radiation Protection

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1 Monitoring and Measurement Approaches P. Schmidt, Wismut GmbH Chemnitz, Germany Head of Department of Env. Monitoring and Radiation Protection IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

2 2 Structure of module Theory: What can we learn from IAEA / ICRP Strategy to develop a site-specific monitoring plan Life cycle of a site-specific monitoring plan Parameters to be measured during different states of a site specific monitoring plan Some general principles for the development of a site specific monitoring plan Case study WISMUT, incl. measurement approaches and QA/QC

3 Theory: ICRP 43 (1984): Principles of Monitoring for the Radiation Protection of the Population IAEA (2005): Environmental and Source Monitoring for Purposes of Rad. Protection, IAEA Saftey Standard Series No. RS-G Source Monitoring Environmental Monitoring Individual Monitoring Operation monitoring; remediation monitoring; Check of sealing functions Source-related environmental monitoring ( fence measurements) Dosimetry, working place measurements Personal-related environmental Monitoring / baseline monitoring Measurement: along environmental media at sites of the critical group

4 Strategy to develop a site-specific monitoring plan 4 Agree on goal of the monitoring task to be solved see also life cycle of a monitoring system Top-down approach historical research (documents) screening measurements (gamma dose rate, sampling in a coarse meshed grid, aerial gamma screening) identify the scope of contamination, the area of concern, the objects of relevance of your site IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

5 Strategy to develop a site-specific monitoring plan Top-down approach (cont.) 5 Identify critical objects (objects with relevant environmental impact) Identify the critical exposure pathways Exposure pathway analysis Identification of the dominating ways of dispersion of contaminants (geological studies, hydrological modelling) Identify the critical group of exposure Identify the best-suitable hard and software for measurement IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

6 Strategy to develop a site-specific monitoring plan Top-down approach (cont.) 6 Identify site-specific conditions that might have an impact on your monitoring system accessibility to the sites (local infrastructure) potential partners (external labs, QA/QC partner) Take the natural background into account Base line studies available?, Bgrd measurements Recognise the relevant regulatory conditions for implementation of a monitoring system Laws, recommendations, requirements regarding reporting/record keeping, QA/QC requirements

7 7 Establish your program Goal Description of the site Field: Measurement points, parameters to be measured Lab: Field sampling / Parameters to be measured Intervals QA/QC program Responsible person Reporting, record keeping

8 8 Life Cycle of a Monitoring System for Existing Exposure Situations Exposure situation Existing Situations Stage Site investigation; Pre-remediation Monitoring Goal Site characterisation data base to decide on justification of remediation data base for modelling, identification of optimised remedial measures Number of measurement Remediation Monitoring assessment of the environm. impact of measures (environment, local public) surveillance of workers (dosimetry etc) time Post-remediation Monitoring monitoring after termination of physical remediation work long-term monitoring proof of remediation success (technical barriers, covers) demonstration of long-term stability of the remedial measures) political aspects (stakeholder expectations, concerns of the local public; epidemiological studies, etc.)) time IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

9 9 Same pictures / examples / remarks / hints / etc. IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

10 Getting started: 10 IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

11 11 Parameters to be measured (1) Air Ambient dose äquivalent rate H*(10) Dust / dust fallout Noise Radioactivity (ll alphas, nuclide-specific concentrations, radon, radon progenies [attached/unattached], AMAD) Water monitoring (surface, groundwater, seepage, releases) Water levels Field parameters (T, ph, Eh, redox potential, turbitity) Radiological parameter (key nuclides, complete nuclide vector: Chemo-toxic parameters, salinity, metals (As, Ni, Cu, Mn, Fe) Soil Specific activities, concentration of non-radioactive substances Biota Specific activities, concentration of non-radioactive substances IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

12 Parameters to be measured (2) 12 Operational Monitoring (water treatment plants) Releases (volumes, radioactivity [load, concentrations], other hazardous substances [load, concentrations]) Parameters governing technological processes Parameters characterizing residues Individual dosimetry, hygienic working conditions Radiological parameters Personal doese equivalent, penetrating Hp(10) Radon/radon progeny concentration, equilibrium factor, AMAD, attached/unattached Rn progenies Long-lived alpha emitters (dust-born) Air quality Dust Aerosols (gases) Noise Geotechnical parameters Seismic parameters, levels, settlements, IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

13 13 Some general aspects and examples of measurements a) The monitoring is site specific as well as object specific, not static and it is subject to regular amendments/optimizations b) Distinction has to be made between the basic monitoring (baseline measurements and person-related environmental monitoring) and object- and/or process-related monitoring of the environmental impact of remedial measures (source monitoring, source-related environmental monitoring) c) Distinction has to be made between controlled releases of radioactivity into the environment and the diffuse radioactivity migration into the air and into aquatic systems IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

14 Monitoring of controlled discharges: water pathway Controlled discharge into receiving streams or underground Typically, such waters are collected and monitored for volume and quality.

14 14 Monitoring of controlled discharges: water pathway Controlled discharge into receiving streams or underground Typically, such waters are collected and monitored for volume and quality. Discharge is from specific hydraulic structures (drainage structures) or from water treatment plants. IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

15 Monitoring of controlled discharge: air pathway Controlled discharges of air-born radioactivity via a ventilation shaft Typically, the air is collected and monitored for volume and quality.

15 15 Monitoring of controlled discharge: air pathway Controlled discharges of air-born radioactivity via a ventilation shaft Typically, the air is collected and monitored for volume and quality. Discharge is from specific structures (ventilation shafts and holes at mine sites, ventilation structures in water treatment facilities) Ventilation shaft #382 at the Schlema site IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

16 Monitoring of diffuse emissions - water pathway Diffuse leakage of seepage and percolating waters into ground and surface waters Quantity and to some extent the quality of such waters can only be

16 16 Monitoring of diffuse emissions - water pathway Diffuse leakage of seepage and percolating waters into ground and surface waters Quantity and to some extent the quality of such waters can only be evaluated by modelling. Their sources are infiltration waters percolating through mine dumps, tailings ponds, and mine workings. IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

17 17 P. Schmidt, Monitoring and Measurement Approaches Monitoring of diffuse emissions - air pathway Radon exhalation, Dispersion of dust-born radioactivity Here: Comparison of radon exhalation rates, summer vs. Winter Legende: <= 0,1 Bq/(m²s) 0,11...0,2 Bq/(m²s) 0,21...0,5 Bq/(m²s) 0,51...1,0 Bq/(m²s) > 1,0 Bq/(m²s) winter, with T outside < 10 O C summer, with T outside > 10 O C IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

18 18 Monitoring: The WISMUT Case Study IAEA Training Course on Remedaition Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

19 Monitoring: The WISMUT Case Study 19 Basic monitoring Continuous surveillance Rehabilitation monitoring Project-related measurements Guideline relating to emission and immission monitoring in mining Monitoring of geomechanical stability Monitoring of non-radioactive components Monitoring of radioactive components Monitoring of the rehabilitation project, for a limited time Long-term monitoring after completion of rehabilitation WISMUT operates one of the largest environmental monitoring systems in Europe samples per year (95 % water samples)are causing database entries.

20 WISMUT Monitoring: Water Pathway 20 EMISSIONS IMMISSIONS ca. 200 monitoring points MINE DRAINAGE WATER SEEPAGE WATER FROM HEAPS and TAILING PONDS GROUND WATER ca monitoring points ca. 350 monitoring points catched WATER TREATMENT PLANT ca. 50 emission points diffuse ca. 200 monitoring points SURFACE WATER RECEIVING STREAMS ca. 130 monitoring points The monitoring network is divided into an emission and immission section to control the discharges and allow dose and risk estimates

WISMUT Monitoring: Water Pathway 21 Over 1800 monitoring

processing waters at 7 former uranium mining and milling

ra-226, U-238) non-radiological p. (As, metals, salinity,.

21 WISMUT Monitoring: Water Pathway 21 Over 1800 monitoring points for observation of ground-, surface, seepage and processing waters at 7 former uranium mining and milling sites. Measured parameters radionuclides (e.g.ra-226, U-238) non-radiological p. (As, metals, salinity,..) hydro-meteorological parameters Annual work volume samplings parameter analysis

WISMUT Monitoring: Air Pathway (2012) 22 Basic Monitoring Air/ground pathway

points) - Rn-222 (234 points) - dust and long-lived alphas (25 points) -

controlled air emissions from water treatment facilities) x air, 12 x water)

22 WISMUT Monitoring: Air Pathway (2012) 22 Basic Monitoring Air/ground pathway (295 meas. points) - Rn-222 (234 points) - dust and long-lived alphas (25 points) - Ra-226 in precipitated dust (33 points) Plus emission points - 2 shafts, - 3 controlled air emissions from water treatment facilities) x air, 12 x water) Remediation monitoring many thousand measurements/a - Rn concentration, Cpot, Rn exhalation - Ambient dose rates, - dust long-lived alpha emitters

23 LIMS / AL.VIS-W LIMS: Laboratory Information Management System 23 AL.VIS-W: Technical Data Base System at WISMUT The ALWIS system has been developed by WISMUT. It is a simple, easy to use, powerful tool to unify geographical and environmental data management.

24 Radon Monitoring at the Schlema site 24 Legende Radonmeßstellen

25 Groundwater monitoring at the Schlema-Alberoda site 25

26 Surface water monitoring at the Schlema-Alberoda site 26

27 27 Sample Taking:... in this way? (picture from the last sample taking?)

28 28 Sample Taking:... or in this way? Most of the errors are due to improper sampling and sample preparation

29 29 QA/QC: Baseline QA/QC I Wismut QA/QC handbook, ISO 9000 conform I Special Department at Wismut I General Instructions, internal guidelines for measurements, accreditation of the laboratories, metrological basis (own calibration facilities), computer added QA/QC, special data bases,... internal certification Process-related QA/QC I I Assurance and control of process-specific parameters Internal certification of successful performance of a certain process

30 30 P. Schmidt, Monitoring and Measurement Approaches QA/QC: Calibration the WISMUT secondary standard calibration fields

31 31 8 m³ - stainless steel chamber View into the Radon- Laboratory with 8 m³ chamber and 400 l containers 400 l containers incl. radon dosing system QA/QC the BfS (German Federal Office for Radiation IAEA Training Course Protection BFS on Remediation in - DKD Infrastructure, Berlin) radon - Calibration Chemnitz, chambers - Germany, Laboratory Dec. 3-7, 2012

32 32 WISMUT monitoring: staff and responsibilities CEO Technical Ressort Authorities Department for Remediation Technology (5) Dep. for data manegement, LIMS and modelling (3) Three external laboratories (VKTA,...) Dep. for Environmental Monitoring and Radiation Protection (10 experts dealing with monitoring) Service Center Env. Monitoring (35) [sampling, doimetery maintenace,...]) Almost 90 experts are dealing with env. monitoring issues (6 % of the WISMUT staff [now 1400] ) reporting Project Management (5) Dep. for QA/QC (1) 3 Labs (central lab in Seelingstaädt, labs in Schlema, Königstein) (30)

33 33 Some lessons learned by WISMUT I Importance of QA /QC (hard and software, staff [training] ) I Site specific monitoring (monitoring for what?) I Purchase only instruments which fit into your infrastructure (robust, spare parts, data transfer, staff qualification,...) I Realize, that most of the errors in environmental monitoring are caused by sampling and sample preparation I Data management (if more than one site data bases) I centralised Apply an intelligent combination of field and lab measurements (screening in the field, focus on key parameters, selected lab investigations, connecting calibration, statistical analysis of field data)

34 34 Measurement approaches Case study: Intelligent Combination of Field and Lab Measurements for Characterisation of Large Amounts of Uranium Production Residues at WISMUT Sites

35 What is the problem? 35 Need of representativ e data Point-wise measurement

36 36 How to manage it? - The batch concept A batch is an assemblage of diverse items (elements, products, goods, but also samples taken from a certain amount of material) which are characterised by same features, or which have the same origin, or which went through similar technological processes. As a consequence, the elements / goods / samples are comparable to each other. Taking of randomly selected samples from this assemblage and analysis of the samples allows to determine parameters which are representative for the batch (charge).

37 37 Intelligent combination between lab and field measurements The problem Contamination at NORM sites may be wide-spread and not homogenously distributed The way out: Intelligent combination of field and lab measurements, statistical data interpretation Step 1: Sampling, determination of the nuclide vector, identification of the index nuclide (lab measurements) Step 2: Selection of an appropriate field (insitu) measurement method Step 3: Problem related connecting - calibration between field and lab measuremts. Step 4: In-situ measurements, quality assurance by laboratory analyses Step 5: Statistical interpretation of the field data

38 Example: Release of lowly contaminated scrap for smelting 38 At WISMUT t scrap from demolition and decommissioning Restricted release criterion: 0,5 Bq/cm² Total Alpha Surface Activity (SSK recommendation) Scrap market price: 100 US $ per tonnes Task: Separation of scrap for release to smelting in a steel factory

Material Ra-226 U-238 Th-230 Rn-222 Pb-210 Waste rocks 1 0.95 0.95 0.94 0.91 U concentrated 0.0013 1 0.0013 0.0009 0.

39 39 Step 1: - make sure that the batch concept is applicable (sorting) - sampling (scratching of rust from the surface), - determination of the nuclide vector, identification of the index (key) nuclide (gamma spectrometry) Dominating Nuclide (=1) Material Ra-226 U-238 Th-230 Rn-222 Pb-210 Waste rocks U concentrated Tailings Pb/ 210 Po IAEA Training Course on Remediation Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

40 Step 2: Selection of an appropriate field (in-situ) measurement method - determination of the Total Surface Alpha Activity TAA via measurement of the

- rationale behind: In the U decay chain is a fixed ratio between alphas and betas - alpha surface activity can under the rough field conditions

40 40 Step 2: Selection of an appropriate field (in-situ) measurement method - determination of the Total Surface Alpha Activity TAA via measurement of the beta net count rate - determination of the beta net count rate requires a double measurement (without shielding N tot ; with a 3 mm Al shielding - N bg ) - rationale behind: In the U decay chain is a fixed ratio between alphas and betas - alpha surface activity can under the rough field conditions (climate, rust) not precisely measured. - using hand-held portable instruments IAEA Training Course on Remediation Infrastructure, Chemnitz, Germany, Dec. 3-7, 2012

41 41 Clearance measurements on surfaces (release of equipment, machinery, scrap) Determination of the beta netto count rate

42 42 Step 3: Problem related connecting - calibration between field and lab measuremts. TAA [Bq/cm 2 ]= k β N β = k β (N tot - N bg ) Calibration pad Simulation of the self-attenuation and backscattering of alpha and beta particles in the rust surface layer not commercially available; self-made, tailored to four different radionuclide vectors

43 Step 4: In-situ measurements, quality assurance by laboratory analyses Screening: Between 50 and 80 measurements for a scrap pile of 50 tonnes 1 scratch sample per pile for QA

43 43 Step 4: In-situ measurements, quality assurance by laboratory analyses Screening: Between 50 and 80 measurements for a scrap pile of 50 tonnes 1 scratch sample per pile for QA (gamma spectrometry) On-site input of the data into a labtop running programme Measurement termination after a certain level of uncertainty for the representative parameter(taa) is reached

44 44 Step 5: Statistical interpretation of the field data investigation of the type of statistical distribution (normal [i. e. Gaussian] distribution via log-normal distribution; note: data on environmental contamination are as a rule lognormal-distributed! consideration of the background Frequency Distribution < 0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 5 Frerquency of the Data Lognorma Distribution Gaussian Distribution [Bq/cm 2 ] Frequency Distribution < 0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 5 [Bq/cm 2 ] Frequency of the Data Lognormal Distribution Gaussian Distribution detection of non-plausible values; exclusion of these values from data interpretation determination of the relevant statistic parameters (X mean, standard deviation σ, uncertainty, percentile P α ; confidence interval for a given level of confidence α) decision on the base of an agreement with authorities (convention) what representative parameter means (for instance with respect to a clearance level, or with respect to the input for a dose estimate)

45 45 Statistical evaluation of the measurement data For a normally distributed measurement quantity, the sample is characterised by estimate of the mean value (E) and deviation (S 2 ). Then the confidence limits for the true mean (µ) may be assessed by the relation S E tα n < µ < E + t n, 1 α, n 1 where tα, n 1 is the percentile of the Student distribution with n-1 degree of freedom for alpha error probability. Only the upper confidence limit defined in (1) is of relevance to check observance of the release level of 0.5 Bq/cm 2, whereby an error probability of α = 0.05 is acceptable. Evaluation of established frequency distributions for TAA data from various scrap heaps would suggest the use of lognormal or approximately lognormal distribution functions for the evaluation of measured data. The upper confidence limit for the true mean µ, which is essential to observe the release limit of 0.5 Bq/cm 2, may then be estimated by the relation S ;exp( / 2) exp ( n t / 2 ) 2 { } ln µ < Max E E + S α + S ln ln, n 1 ln where E ln and S 2 ln represent the estimate of the mean value and deviation of the lognormal distribution. S n (1) (2)

46 46 Statistical evaluation of the measurement data Comparison of the TAA reference value (0,5 Bq/cm²) with the upper limit of the confidence interval (95 % confidence value) 120 Frequency Distribution Frequency of the Data Lognormal Distribution Gaussian Distribution TAA mean value = 0,11 Bq/cm² Upper confidence limit = 0,14 Bq/cm² 0 0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 [Bq/cm 2 ] Frequency distributions of TAA values for a heap of scrap metal of Wismut GmbH

47 IAEA Project BRA3013, Workshop, Poços de Caldas, June 2011 P. Schmidt; Environmental Monitoring at Uranium Mining and Milling Sites 47 Many Thanks For Your Attention 47

Management of Radioactive Residues & Wastes Generated During Remediation of Uranium Production Legacy Sites in Germany

Management of Radioactive Residues & Wastes Generated During Remediation of Uranium Production Legacy Sites in Germany Peter Schmidt, Wismut GmbH Chemnitz, Germany Head of Department of Environmental Monitoring