ISO Standard of Waste Activity Evaluation Method for Contaminated and Activated waste

Transcription

1 ISO Standard of Waste Activity Evaluation Method for Contaminated and Activated waste November / 2012, IAEA LABONET in Brussels, Belgium M. Kashiwagi

2 Developing Activity Evaluation Method for DTM nuclides: Application method and Target waste Main Activity Evaluation method Target wastes Waste Examples ISO Standard Empirical method: Scaling factor method (SF method) Contaminated waste Concentrated liquid, Spent resin, DAW, etc. ISO Theoretical method: Activation calculation method Activated waste Control rod, Channel box, Burnable poison, etc. ISO16966 (DIS) Under developing DTM nuclides: Difficult to measure nuclides such as C-14, Nb-94, α emitters DIS: Draft of International Standard (Now voting) 1

3 Published ISO International standard and IAEA technical document for SF method ISO Standard (ISO21238:2007) (Describe basic methodology) IAEA Document (NW-T-1.18:2009) (Gathering many country s practices) Scaling factor method for L& ILW generated at NPP Determination and Use of Scaling Factors for Waste Characterization in NPPs Property: Basic Manual Property: Text book, Examples ISO21238 was published in April NW-T-1.18 was published in 2009.

4 ISO Standardization: ISO21238 Member of Project Team for Developing ISO Standard of SF Method No ISO Participant Country TC85 SC5 Project Team 1 Argentina (IRAM) CNEA, NRA 2 Belgium (IBN) ELECTRABEL 3 Canada (SCC) OPG 4 China (SAC) France (AFNOR) EDF 6 Italy (UNI) Japan (JISC) TEPCO, JGC 8 Kenya (KEBS) Korea (KATS) Russian Federation(GOST R) Spain (AENOR) ENRESA 12 Sweden (SIS) SKB, Ringhals 13 United Kingdom (BSI) BE, BNFL, UKAEA 14 USA (ANSI) EPRI, Consultant 15 Austria (ON) Bulgaria (BDS) Switzerland (SNV) -- NAGRA 18 Netherlands(NEN) -- NRG, NEN 19 Germany (DIN) ISTec Project team was consisted of Nominated experts from 19 institutes from 12 countries. TC85: Nuclear Energy SC5: Nuclear fuel cycle : Convener : Participant member 3

5 Scope : ISO Standard of Scaling Factor Method Sampling and Radiochemical analysis of Radioactive waste Individual Waste package Evaluation of the data DTM Nuclide SF Key Nuclide Correlation is confirmed Non- destructive measurement Waste package scan ISO21238 covered these parts. Value of SF (DTM / Key nuclide) Radioactivity of Key nuclide (Co-60,Cs-137) Radioactivity of DTM nuclide rotation ISO14850 covered DTM: Difficult to measure nuclide (such as C-14, Ni-63 etc.) 4

6 ISO 21238:2007 Contents of ISO Standard of SF Method for L/ILW Chapter Common item Chapter 4. Sampling 4.1 Representative sampling 4.2 Rejection of outlier 4.3 Record of sample Chapter 5. Evaluation Methodology 5.1 Applicability of Scaling Factor method 5.2 Evaluation by linear relationship 5.3 Evaluation by nonlinear relationship 5.4 Selection of Key nuclides 5.5 Integration and classification methodology for Scaling factor 5.6 Scaling Factor accuracy

7 IAEA Nuclear Energy Series: NW-T-1.18 Contents of IAEA document of SF Method 1. Scaling factor basis Basic philosophy (Empirical method based on similarity production & behavior) Basis of evaluation (Log-normal distribution & Correlation) 2. Scaling factor method application Application principle (steps of basic application manner) Summary of application practices in selected member states 3. Commonality and consensus in scaling-factor programs Evaluation of influencing factors (component material, fuel and physic-chemical property) Evaluation of application methods (Key nuclide, calculation method, trend evaluation and international integration) etc. 4. Quality management Quality management in each developing stage Annexes : 20 country s Practices of SF method

8 ISO 21238: 2007 Chapter 5. Methodology Calculating Method Calculating method of Scaling factor Actual distribution (Ni-63/Co-60) There are two recommended manners for calculating Scaling factor. A. Geometrical mean - Based on linear relationship of DTM nuclide and key nuclide - Based on the log normal distribution B. Linear regression of logarithm Actual scatter diagram (Ni-63/Co-60) - Based on non-linear relationship of DTM nuclide and key nuclide - Based on log normal regression.

9 IAEA Document: NW-T-1.18 Actual Practices of Selection of Calculation Method of SF Scaling factor calculation method for determining the radioactive concentrations of DTM nuclides in waste packages, most countries, as shown in following Table, are determining or planning to apply the Geometrical mean or Logarithmic regression. Calculation Method Share of application Geometrical mean (log mean) Around 50 % Linear regression of logarithms Around 40 % Arithmetical mean Around 10 %

10 ISO 21238: 2007 Chapter 5. Methodology Classification methodology Classification of wastes Setting appropriate SF required consideration of classification based on following conditions. - Reactor component materials (--> CP nuclides) - Fuel stability (--> FP nuclides and α emitters) - Volatile property (--> C-14) etc. Integration of wastes It is possible to integrate to many country s data under consideration of above classification.

11 IAEA Document: NW-T-1.18 Classification methodology by influence factor CP Nuclide (Ni-63/Co-60) (Component Material) FP Nuclide(Alpha/Cs-137) (Fuel stability) C-14 in BWR (C-14/Co-60) (Volatile property) Sampling should be carried out in consideration of following factors: - Plant type (BWR and PWR, difference in reactor component material ) - Fuel stability group (Fuel is stable, Slight fuel failure, Large fuel failure ) - Waste stream (Example: The case of C-14 in BWR )

12 ISO 21238: 2007 Integration and Classification by the Type of Waste for CP Nuclide Similarity in the CP Nuclides There is no appreciable difference - in the ratio of DMT nuclides and Key nuclide between type of waste in the same type of plants. - between the physicochemical behavior in each CP Nuclide. Key Nuclide Appropriate waste classification for SF evaluation Co Unified SFs can be established irrespective of the type of waste. 2. However, if classification is needed for the purpose of more detail estimation, classifying is not restricted.

13 IAEA Document: NW-T-1.18 Integration of waste stream and type of waste Example: CP Nuclides : Ni-63/Co-60 - Japanese PWR Ratio(%) Reactor Coolant Japanese PWR Probability Spent Resin Liquid waste Concentrates Cartridge Filter DAW Solid waste Type of Waste Reactor Coolant Spent Resin Concentrates Cartridge Filter DAW TOTAL Correlation Coefficient Geometrical mean 7.1 E E E E E E - 1

14 IAEA Document: NW-T-1.18 Integration of international radiochemical analysis data which collected independently. CP Nuclides : Ni-63/Co-60-3 Country s PWR plants Ratio(%) Japan Probability France Liquid waste Germany Japan France Solid waste Type of Waste Japan Liquid waste France Liquid waste Germany Liquid waste Japan Solid waste France Solid waste Correlation Coefficient TOTAL Geometrical mean 5.1 E E E E E E - 1

15 ISO International Standard and IAEA Document for Theoretical Activity Evaluation Method ISO Standardization (ISO DIS16966) (Describe basic methodology) Developing ISO16966 (DIS), Theoretical activation calculation method to evaluate the radioactivity of activated waste generated at nuclear reactor Property: Basic Manual Standard has been developing in ISO Project team. ISO16966 will be published by the end of DIS: Draft of International Standard IAEA Document (Gathering many country s practices) IAEA Nuclear Energy Series, Examples and Practices of Theoretical activation calculation method for Characterization Property: Text book, Examples Just planning.

16 No ISO Project Team Member List for Developing Theoretical Evaluation method (ISO16966) ISO Participant Country TC85 SC5 Project team 1 Argentina (IRAM) NRA 2 Belgium (NBN) SCK/CEN 3 Bulgaria (BDS) Canada (SCC) NWMO 5 China (SAC) France (AFNOR) EDF, AREVA 7 India (BIS) Iran, Islamic Republic of ( ISIRI ) Japan (JISC) JGC, Utility 10 Kenya (KEBS) 11 Korea (KATS) KEPCO NP 12 Russian Federation (GOST R) Spain (AENOR) ENRESA 14 Sweden (SIS) SKB 15 Switzerland (SNV) NAGRA 16 United Kingdom (BSI) USA (ANSI) DW James Consulting 18 Ukraine ( DSSU ) Austria (ASI) Italy (UNI) Germany (DIN) -- ISTec (Obs.) 22 Netherlands (NEN) Project team was consisted of nominated experts from 13 institutes from 12 countries. Project team has been developing Standard from : Convener : Participant member 15

17 Apr.7 vote closed Dec.12 vote closed 3 ISO Standardization Process New Work Item Proposal (NWIP) Committee Draft (CD) Draft of International Standard (DIS) 2013.Jan.7 vote closed Vote result: 12 country s experts Vote 2011.Jun.02, CD registered Vote result: 14 country s YES 2012.August, DIS registered - Show the skeleton of target standard - Collection of experts for project team from Member Body (MB) Approval condition: NWIP approved at least 5 countries to participate actively in the project - Show the draft of Standard to MB - Collect comments to the draft from MB Approval condition : CD is needed consensus (general agreement), treat as same as condition of DIS vote. - Show the revised of Standard to MB - Collect final comments to the standard from MB 4 5 Final Draft of International Standard (FDIS) Vote International Standard (Published as ISO Standard) - Show the Standard to MB - Final vote to the Standard for publishing Approval condition : DIS & FDIS approved if a 2/3 of the members of the TC/SC are in favor and not more than 1/4 of the total number of votes are negative. 16

18 Main Activity estimation methods in ISO Outline of Point and Range estimation methods Outline of method Usage Point Estimation Method Calculate concentration or ratio of nuclides at specific point in the waste (mainly in one activated radioactive waste) or representative (maximum or conservative) point of waste. - Evaluation of inventory for safety assessment of disposal in the planning stage. - Evaluation of activity concentration of specific waste for verifying theoretical evaluation method etc. Range Estimation Method Evaluated average or distribution of concentration or ratio of nuclides by calculating many assumed irradiation points. (Assumed evaluation points selected randomly which are covered all condition of irradiation). - Evaluation of activity concentration of waste packages for declaration to dispose.

19 ISO DIS16966: Basic Plan and Contents of ISO Standard Clause Common item Clause 3. Theoretical evaluation method 3.1 General 3.2 Point estimation method 3.3 Range estimation method Clause 4. Calculation 4.2 Selection and determination of input conditions Input parameters Elemental composition Neutron fluence rates Irradiation conditions 4.3 Activation calculation Calculation code Setup input data Determining number of calculations 4.4 Validation and uncertainties 4.5 Records Category of Method Theoretical evaluation method is classified 2 categories. (Detail is specified in Annex A) Calculation basis Basic calculation condition (Input data and calculation manner). (Detail will be specified in Annex B and C) Validation, etc. Quality control. (Detail will be specified in Annex D and E) 18

20 ISO DIS16966: Outline of Range Estimation Methods Image of Evaluation Conversion Coefficient method Concentration of Evaluated nuclide(bq/t) Correlation method DTM nuclide(bq/t) Averaging Method Calculation value Represented Value Represented Value Outline of Evaluation method Target waste There is close relation between Key index, such as burnup (normally fuel is controlled by burnup) and the concentration of DTM nuclide in activated component. The concentration of DTM nuclide is able to evaluate as conversion coefficient by activation calculations considered the range of actual reactor condition (e.g. element, neutron, irradiation condition). Channel box, Control rod, Burnable poison, etc. There are specific relations among simultaneously generated nuclides in the same part (that is, neutron, elemental composition, irradiation time are same) of activated component. The ratio of DTM nuclide and Key nuclide are able to calculate by activation calculations considered the range of actual reactor irradiation condition. Waste Type A Elemental composition and irradiation condition are almost same in fixed equipment. The difference of nuclide's concentrations is generated by the difference of neutron condition. The concentrations in the reactor component or parts of reactor are calculated by activation calculations considered the range of actual reactor condition and position of equipments. Graphite block, Core shroud, Pressure vessel, etc. Waste Type B 19

21 ISO DIS16966: Basic flow of Setup Input Database for Range Estimation Method Selection of activated waste Study of property and irradiation history of target waste. Selection of evaluation point Selection of concentration of elemental composition Selection of loading position in operation cycles Fixing neutron condition at Selected point in reactor No Setup of input data Sufficiency (at random for Range method) (at random for Range method) (at random for Range method) Yes Completion of input database Irradiation Time (at random) Activation Cross section Selection of the evaluation point in the waste based on shape of waste. (at random) Setup of the concentration of the parent element based on concentration distribution of chemical analysis data. (at random) Setup of the irradiation time and the neutron condition which were based on the operational cycle of reactor and the loading position in the reactor. (at random) Normally, activation cross section prepare from library of calculation code. If database dose not reach sufficient number of input data, continue to select next evaluation point and condition. Sufficient number of input data are created and activation calculations are carried out. 20

22 ISO DIS16966: Image of Setup the input data for Activation Calculation 1 Activation point in target waste Example of channel box Loading position in the reactor Rotation of fuel load position in reactor Irradiation condition (Neutron flex) Example of thermal neutron flex Select right thermal neutron flux based on the selected position in activated metal and rotation of fuel load position. Random sampling (from uniform distribution) Random sampling based on ratio of several represented fuel rotation patterns. Select neutron flux based on activation point and loading position among fuel cycles. 21

23 ISO DIS16966: Image of Setup the input data for Activation Calculation 2 Concentration of chemical elemental composition in target waste Distribution of element concentration Average and standard deviation of distribution are determined based on chemical analysis data of cold samples of CB/BP/CR etc.. Irradiation condition (Irradiation time) Irradiation time (Example) Assume normal distribution of total irradiation time based on distribution of actual reactor operation time from 13,000 BWR fuel assembly s records. Setup Average and Standard deviation from actual distribution of total irradiation time. Random sampling Random sampling 22

24 ISO DIS16966: Result of Range Estimation Method Calculation result of Channel box (ZrTN804D:Zircaloy) in BWR plant. Scatter diagram Nb-94/Co-60 Distribution diagram Nb-94/Co-60 Log-normal probability diagram Nb-94/Co-60 Correlation coefficient: 0.83 Good correlation Seemed good log-normal distribution Seemed good lognormal distribution 23