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Main text Since 1976, 23 laboratories have submitted 44 samples of 134Cs to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Cs-134. In the last few years, the POLATOM (Poland), the NRC (Canada), the LNMRI-IRD (Brazil) and the PTB (Germany) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR or linked to the SIR from the APMP.RI(II)-K2.Cs-134 comparison and the updated KCRV have been calculated and the results are given in the form of a table. A graphical representation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Three new participations in the BIPM.RI(II)-K1.I-131 comparison have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the CCRI(II)-S6.I-131 comparison piloted by the International Atomic Energy Agency (IAEA) in 2006, based on the participation of CMI-IIR in both comparisons. One NMI used the S6 comparison to update its degree of equivalence. The results of two NMIs in the CCRI(II)-S6.I-131 comparison were superseded by a more recent APMP.RI(II)-K2.I-131 comparison. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for the latest results in the BIPM.RI(II)-K1.I-131, and the linked CCRI(II)-S6.I-131, APMP.RI(II)-K2.I-131 and EURAMET.RI(II)-K2.I-131 comparisons. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Since 1976, 15 laboratories have submitted 39 samples of 88Y to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Y-88. Recently, the LNE-LNHB (France) and the BEV (Austria) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Since 1979, 8 laboratories have submitted 20 samples of 201Tl to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifer BIPM.RI(II)-K1.Tl-201. The NIST (United States) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Three new participations in the BIPM.RI(II)-K1.Co-57 comparison have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the CCRI(II)-S6.Co-57 comparison piloted by the International Atomic Energy Agency (IAEA) in 2008 for which one sample of the 57Co radioactive solution was sent to the SIR. Two NMIs used the S6 comparison to update their degree of equivalence. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for the remaining seven NMIs in the BIPM.RI(II)-K1.Co-57 comparison and the three eligible participants in the CCRI(II)-S6.Co-57 comparison. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

A bilateral comparison between ENEA-INMRI (Italy) and NCBJ RC POLATOM (Poland) of 131I-solution activity measurements was organized in the year 2015 and piloted by POLATOM, which provided the sources for the comparison. The 131I master solution was standardized independently at both institutes by using Liquid Scintillation Counting and ionization chamber techniques. The 131I master solution was then sent by POLATOM to the BIPM International Reference System (SIR). The comparison was registered as an EURAMET.RI(II)-K2.I-131 key comparison allowing the ENEA-INMRI result to enter in the SIR database.

Main text Since 2014, 3 laboratories have submitted 3 samples of 223Ra to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ra-223. The NPL (United Kingdom), the PTB (Germany) and the LNE-LNHB (France) participated in the comparison and the key comparison reference value (KCRV) has been calculated for the first time. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Since 1978, 10 laboratories have submitted 17 samples of 67Ga to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ga-67. The PTB (Germany) and the NIST (United States) participated in the comparison. The key comparison reference value (KCRV) has been re-calculated using the power-moderated weighted mean. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Since 1983, 6 laboratories have submitted 7 samples of 110mAg to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ag-110m. Recently, the PTB (Germany) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

During a severe accident in a Pressurized Water Reactor, corium may fall in the reactor pit and interact with concrete. The CLARA facility, financed by EDF, IRSN, GDF-Suez and CEA, has been designed to understand the heat transfer phenomena involved in the Molten Concrete–Corium Interaction (MCCI). The facility is composed of a pool of simulant liquids, percolated by air and internally heated by direct electrical current. It is in contact with several heat exchangers in order to maintain walls at a constant temperature and to measure local heat losses. The experiments performed aimed at studying the influence on heat transfer of liquid viscosity (varying from 1 to 10,000 mPa.s by dissolution of hydroxyethyl cellulose in the water), air injection superficial velocities (ranging from 0 to 10 cm/s) on both horizontal and vertical walls, and pool length. After a literature review on the existing heat transfer experiments and correlations for two-phase (liquid–gas) flow, the CLARA experiments are described. Then, the results obtained are presented: influence of superficial gas velocity and liquid properties (especially viscosity) on heat transfer, evaluation of ratio between heat transfer on vertical and horizontal interface, influence of the pool dimensions. Finally, the analysis and interpretation of CLARA experiments are given: comparison to the literature data, development of correlations concerning the heat transfer along the vertical and horizontal plate, comparison to results obtained with real materials. The results show that the presence of bubbles enhances heat exchange while an increasing viscosity lowers the heat transfer. The MCCI isotropic trends are different from those observed with prototypical materials suggesting that phenomena occurring at the corium–concrete interface are more complex than the ones present in CLARA experiments.

Since 1976, 13 laboratories have submitted 29 samples of 22Na to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)- K1.Na-22. Recently, the LNE-LNHB (France) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Three new participations in the BIPM.RI(II)-K1.Fe-59 comparison have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the APMP.RI(II)-K2.Fe-59 comparison held in 2014 through the NMIJ who participated in both comparisons. Five NMIs used the K1 or K2 comparison to update their degree of equivalence. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for the remaining five NMIs in the BIPM.RI(II)-K1.Fe-59 comparison and the eight other participants in the APMP.RI(II)-K2.Fe-59 comparison. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

This report summarises the results for the new BIPM.RI(II)-K1.Ge-68 comparison. Six metrology institutes have participated, enabling the first value of the key comparison reference value(KCRV) to be determined. The KCRV was calculated using the power-moderated weighted mean and the results. A link has been made to the CCRI(II)-K2.Ge-68 comparison held in 2015 through the NIST, NIM,IRA-METAS and the LNE-LNHB who participated in both comparisons. One NMI used the K2 comparison to update their degree of equivalence. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for the remaining five NMIs in the BIPM.RI(II)-K1.Ge-68 comparison and the 12 other participants in the CCRI(II)-K2.Ge-68 comparison. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

This paper discusses basic theoretical strategies used to deal with measurement uncertainties arising from different experimental situations. It attempts to indicate the most appropriate method of obtaining a reliable estimate of the quantity to be evaluated depending on the characteristics of the data available. The theoretical strategies discussed are supported by experimental detail, and the conditions and results have been taken from examples in the field of radionuclide metrology. Special care regarding the correct treatment of covariances is emphasized because of the unreliability of the results obtained if these are neglected.

A bilateral comparison between ENEA-INMRI (Italy) and NCBJ RC POLATOM (Poland) of

This report concerns an international comparison of measurements of a solution of 238Pu that was carried out by 12 participants in 2001. The report includes the degrees of equivalence. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

This article reviews the tools available to assign realistic uncertainties in the field of radioactivity measurements following the prescriptions of the Guide to the Expression of Uncertainty in Measurement. A presentation of different distributions that can be encountered in the analysis of radioactivity measurements is listed, and explained using simple but pertinent examples. Two different methods, a simplified coincidence method and ? counting, are considered, for each of which a detailed uncertainty budget is given. This leads into the characteristics function and the law of propagation of errors that can be used in the evaluation of the total uncertainty. The treatment of correlations, which occur when using the same set of sources and the same decay period for both methods, is also detailed.Subsequently, the analysis of the results of a comparison of activity measurements made by various national laboratories is presented with special care regarding the treatment of correlations that may arise.Finally, the paper also deals with the KCRV determination and the evaluation of degrees of equivalence between laboratories in the general case where the results of BIPM, CCRI and RMO comparisons are linked together. In this case too, as far as is practical, a method to treat correlations is described.While the illustrations in this paper are focused on radioactivity measurements, most of the material presented can, when appropriate, be used in other domains of metrology.

The paper begins with the reasons which led to the installation of the Systeme International de Reference (SIR) more than 30 years ago, describes its main features and presents briefly the way it works. Then more detail is given on the treatment of impurities and on the determination of the efficiency curve. The improvements, which have been made recently to update the SIR and make it more efficient, are also discussed. A brief survey of the status of the present SIR is then given before focusing on the new developments which are in progress to enlarge the scope of the SIR towards measurements of radiopharmaceuticals with short half-lives and of α- and β-particle emitters.

In response to the CIPM MRA, and to improve radioactivity measurements in the face of advancing technologies, the CIPM's consultative committee on ionizing radiation developed a strategic approach to the realization and validation of measurement traceability for radionuclide metrology. As a consequence, measurement institutions throughout the world have devoted no small effort to establish radionuclide metrology capabilities, supported by active quality management systems and validated through prioritized participation in international comparisons, providing a varied stakeholder community with measurement confidence.

International audience; Liquid scintillation counting is a very powerful technique for the activity determination of a number of radionuclides. In radionuclide metrology, the TDCR method and the CIEMAT/NIST efficiency tracing technique are widely used in many laboratories. Both methods require rather complex calculation techniques to derive the counting efficiency of the nuclide under study. This article explores the various sources of uncertainty that should be considered when applying these two techniques, and focuses on possible ways to evaluate them. Concrete examples are provided within the paper.

In the analysis of the results of an international comparison it is not exceptional that one or even several values are not in line with the others. It is often difficult to find good reasons—empirical or even statistical—for rejecting these data that may strongly influence the reference value. The median has been recognized as useful for the analysis of comparisons in the field of radioactivity as it avoids the need to cope with outliers. In this paper, the median is used as the key comparison reference value (KCRV) and the formulae necessary to evaluate its uncertainty and that of the degree of equivalence are given. In addition, the weighted median is also defined for use as the KCRV. Equivalent formulae are deduced for this estimator. This paper thus enlarges the range of concepts published previously for KCRV estimators.

Some formulae used for evaluation of the uncertainties of the degree of equivalence between laboratories participating in an international comparison of activity measurement are presented. Two approaches are considered using two different estimators for the key comparison reference value: the arithmetic mean and the weighted mean. For each approach, four cases which can be encountered when dealing with comparison data are detailed. Finally, the effect of the uncertainties on the weights used in the second approach is also considered. This work has been developed for analysis of results of comparisons organized in the field of ionizing radiations, but the formulae are sufficiently general to allow their use for other comparisons. However, correlations between results have not been considered.

This paper reports contributions from participants in the EUROMET project (No. 416) which was entitled "237Np research into problems relating to purification, characterization and standardization". Primary standardizations were made by the defined low solid angle, coincidence, 4pi alpha, 2pi alpha and liquid scintillation counting methods. Secondary standardizations were made with calibrated gamma-ray spectrometers. Absolute X-ray, gamma-ray and alpha-particle emission probabilities were also determined. The results for the successful conclusion of both primary and secondary standardization are presented together with the values for alpha-particle and gamma-ray emission probabilities determined in this exercise. Several significant inconsistencies remain with the gamma-ray emission probabilities, and these are highlighted.

Since 2010, four national metrology institutes (NMI) have each submitted a sample of known activity of 60Co to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Co-60. The values of the activity submitted were between about 175 kBq and 1600 kBq. The primary standardization results for the CNEA, Argentina and the BARC, India replace their earlier result of 2003 and 2001, respectively. There are now seventeen results in the BIPM.RI(II)-K1.Co-60 comparison. The key comparison reference value (KCRV) has been updated using the power-moderated weighted mean. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Since 2009, three national metrology institutes (NMI) have submitted three samples of known activity of 241Am to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Am-241. The values of the activity submitted were between about 3 MBq and 38 MBq. These three results replace their earlier results obtained in the linked CCRI(II)-K2.Am-241 in 2003. There are now five results in the BIPM.RI(II)-K1.Am-241 comparison, 16 results remaining from the CCRI(II)-K2.Am-241 comparison and two results in the COOMET.RI(II)-K2.Am-241 comparison. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV dating 2007 have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The toroidally-viewing spectroscopic imaging system on Tokamak de Varennes (TdeV) [F. Meo et al., Rev. Sci. Instrum. 68, (1997)] has given new insight into the physics of a closed divertor, where the particles interact with a vertically oriented inclined plate situated upstream from the target plate. The system has enabled two-dimensional (2D) measurements of the absolute emissivities of Hydrogen Balmer lines, as well as Carbon lines. Using the Balmer ratios, the poloidal profile of the electron density has been calculated using a Collisional-Radiative model [K. Sawada and T. Fujimoto, J. Appl. Phys. 78, 2913 (1994)]. Results show that the plasma parameters are locally affected by the divertor components particularly the inclined plate. This inclined plate constitutes an extra recycling surface which causes an increase in the atomic density and a decrease in the electron density in this region and affecting the plasma parameters at the target plate. Finally, the calculated poloidal plasma parameters are p...

The harmonization of different National Measurement Systems depends on the ability to demonstrate Equivalence between them. The responsibility for establishing a procedure to achieve this lies with the International Committee of Weights and Measures (CIPM) and its associated Consultative Committees. In pursuit of these ends, a series of general recommendations and procedures have been developed by BIPM in order to achieve these objectives. Central to these recommendations is the concept of Key Comparisons which involve a series of comparison exercises both within and between the regional metrology organizations, such as EUROMET, NORAMET and APMP. Because of the unique nature of radioactivity standardization, this generalized procedure is, for practical purposes, impossible to apply in the field of radionuclide metrology. The remedy has been the development of a protocol which optimizes both the current effort available within existing National Metrology Institutes (NMIs) and the considerable amount of data from previous intercomparisons. This paper details this novel approach, provides practical examples, discusses potential problems and examines the way in which the programme will continue and expand.

Simulations of carbon transport using the DIVIMP code [P.C. Stangeby, J.D. Elder, J. Nucl. Mater. 196–198 (1992) 258] are compared with 2D toroidal images of CII and CIII radiation near the external divertor plates in TdeV ohmic plasmas ( I p =170 kA, n e =3 × 10 19 m −3 , B T =1.4 T ). The main plasma parameters in the SOL and divertor are calculated by the onion skin model (OSM) [K. Shimizu et al., J. Nucl. Mater. 196–198 (1992) 476] included in DIVIMP, the neutrals being calculated by EIRENE [D. Reiter, Internal Report, KFA, Julich, 1947 (1984), 2599 (1992)] in an iterative loop. The results show that the carbon is mainly created by chemical sputtering, with a considerable fraction coming from the external oblique plate. By interpreting experimental CII and CIII distributions, it is found that carbon is affected by the biasing (−125 to +125 V) through a combination of at least three processes: the ion flux to the plates, the E × B drift velocity, and the cross field diffusion.

A toroidally viewing spectroscopic imaging system has been developed for the Tokamak de Varennes providing measurements of the poloidal distribution of the absolute radiated power of deuterium and impurity species in the upper divertor region. Real time digitization is achieved using a low cost PC based digital imaging system. This system is used to obtain measurements of the divertor strike point as well as the shape of the flux surfaces in the divertor. The diagnostic’s excellent spatial resolution and toroidal view provides an opportunity to quantitatively compare the measured two dimensional (2D) radiated power distribution to that calculated from 2D Monte Carlo transport codes. These 2D images provide unique and valuable information on the physics of local plasma interactions with divertor components and particle transport in a closed divertor. Additionally, by using two cameras simultaneously, the line ratio technique can be applied to the images to estimate plasma parameters in the divertor.

At high densities, the plasma detaches from the outboard divertor plates in TdeV. The signatures are a reduction of the ion flux to the divertor plate, movement of the radiating zone from the plate toward the X-point, a pressure gradient between an ionization front and the target plate, and strong cross-field transport in the divertor. A toroidally-viewing TV imaging system allows us to observe local interactions between the divertor plasma and the different divertor plates. As the plasma detaches, the gas pressure in the divertor continues to rise, and there is evidence for molecular processes in the cold plasma near the divertor plates. Auxiliary heating increases the power and particle flow across the separatrix; our results suggest that detachment depends on the energy transported per particle. Simulations using the B2/EIRENE and DIVIMP codes give reasonable agreement with the measurements for the attached phase.

Impurity concentration and transport are studied by interpreting line emissions in the VUV and soft X-ray emission, using the MIST impurity code. Standard tokamak discharges have been used with modest divertor plate bias voltages Vb (-300 to +300 V). The intrinsic impurities studied are oxygen and carbon. Neon, an extrinsic impurity, is introduced using hydrogen gas fuelling with a 0.3% trace of neon. Aluminium is introduced by laser ablation. The radial profiles of C IV emissivity show an increasing diffusivity from negative to positive biasing, while to obtain compatible changes between the VUV emissions (C IV, O VII and Ne IX) and the soft X-ray profiles, the inward convection velocity and the impurity concentrations must be increased as Vb increases from -300 V to +300 V. The changes in the convection predicted by six different models are compared with the experimentally deduced convection. These models are based on ion mobility, ion orbit losses, anomalous viscosity caused by turbulence, the skin size electromagnetic drift mode, neoclassical theory in the presence of turbulence and mobility related to E*B turbulent diffusivity. This comparison allows the changes in the convection velocity to be related qualitatively to the ambipolar radial electric field Eamb, which may be different from the purely neoclassical value Eneo, owing to turbulence which is usually intrinsically non-ambipolar; the turbulence can also cause an anomalous viscosity, affecting the rotational velocities and hence Eamb

Since 2001, six national metrology institutes (NMI) have submitted seven samples of known activity of 18F to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.F-18. The values of the activity submitted were between about 1 MBq and 18 MBq. The primary standardization result for the LNE-LNHB, France, replaces their earlier result of 2002 and the key comparison reference value (KCRV) has been recalculated. In the frame of the BIPM.RI(II)-K4.F18 comparison, the NPL updated their result in the KCDB. Consequently there are now five results in the BIPM.RI(II)-K1.F-18 comparison. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Since 1975, seven national metrology institutes (NMI) have submitted eleven samples of known activity of 113Sn to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Sn-113. The values of the activity submitted were between about 0.7 MBq and 22 MBq. The present primary standardization results for the PTB, Germany and the LNE-LNHB, France, replace their earlier results of 1989 and 1992, respectively. A key comparison reference value (KCRV) has been evaluated for the first time for 113Sn. There are only three results remaining in the BIPM.RI(II)-K1.Sn-113 comparison, all the previously published ones being outdated. The degrees of equivalence between each of these three equivalent activities measured in the SIR and the KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The purposes of this study were to create national activity standards of (64)Cu, to make possible the definition of an international key comparison reference value and to determine the decay data in order to improve the decay scheme. Four laboratories measured the activity of a (64)Cu solution; these results were compared through the International Reference System. Moreover, the laboratories carried out new measurements of the photon emission intensities and of the half-life. A new decay scheme was derived from these new values and the previously published ones.

Within the SARNET network of excellence in the 6th Framework Programme of the European Commission, the severe accident integral code ASTEC, jointly developed by IRSN (France) and GRS (Germany), has been validated against international experiments to evaluate the suitability and capability of new or improved models implemented in successive code versions up to V1.3rev2, delivered in December 2007. This paper focuses on the code applications concerning circuit thermal-hydraulics and core degradation to integral and separate-effect experiments: for the CESAR thermal-hydraulic module, BETHSY 9.1 b, PACTEL ISP 33 and T2.1, PMK2-SBLOCA, LOFT-LP-FP-2; for the DIVA core degradation module, CORA-13 and -W2, QUENCH-11 and -13, LOFT-LP-FP-2, Phébus FPT-4, FARO L14 and L28, LIVE-L1, OLHF-1, FOREVER EC2. Besides, the TMI-2 accident has been analyzed using the CESAR and DIVA modules in a coupling mode. The emphasis was put on the following new or improved models: i.e. in CESAR, reflooding of an intact core, condensation in the pressurizer, sub-critical break flow correlation, and new pressurizer spray model; in DIVA, corium behaviour in the lower head and lower head mechanical failure. For thermal-hydraulics in the circuits, good results have been obtained with ASTEC on the three integral experiments that cover various thermal-hydraulic flow regimes: LOFT-LP-FP-2 in Western PWR geometry and the two PACTEL experiments in VVER-440 geometry. These good results have been confirmed by the validation done on several BETHSY integral tests. For core degradation, the ASTEC results are good for early-phase models of core heat-up, oxidation and hydrogen production (before any quenching phase) on different CORA and QUENCH experiments and on LOFT-LP-FP-2. For the in-vessel late-phase, the results can be considered as good regarding debris bed melting (Phébus FPT-4), corium fragmentation at slump into vessel lower plenum (FARO), molten pool behaviour in lower plenum (LIVE-L1), and vessel lower head mechanics (OLHF-1 and FOREVER EC2). Furthermore, the first two phases of the TMI-2 accident before core reflooding are very well calculated by ASTEC. The main remaining modelling weaknesses concern the reflooding of a degraded core and the corresponding hydrogen production. The implementation of detailed magma 2D relocation models in the new series of ASTEC V2 versions (the first one being released mid-2009) will allow a more realistic simulation of late phase phenomena up to the failure of the lower head. © 2009 Elsevier Ltd. All rights reserved.

Preparation of the internal walls of tokamaks by plasma enhanced chemical vapour deposition (PECVD) of boron containing films has now been implemented on several machines since its development on TEXTOR. More recently, such films were deposited on the internal walls of TdeV using not only this procedure but also two new approaches: solid target boronization (STB) which consisted in inserting a low-density boronized carbon-carbon (C-C) composite into the tokamak plasma and TMB fuelling where trimethylboron was used as fuelling gas during the plasma discharge. These approaches resulted in a rapid shot to shot improvement of important parameters such as the volume averaged resistivity and radiated power over the first dozen shots when the boron source is present. Typically, the resistivity is reduced from ∼4.0×10 −7 to ∼2.5×10 −7 Ωm, comparable to the resistivity obtained with PECVD. The radiated power relative to the ohmic power is reduced by a factor of 2 from 20 to 10%. When the boron source, present during STB or TMB fuelling, is removed however, these plasma parameters start increasing. Within a few tens of shots, they have reverted to their preconditioning values, a situation which requires hundreds of shots after PECVD.

A comparison exercise for data analysis was recently conducted by the Liquid Scintillation Counting Working Group (LSCWG) of the International Committee on Radionuclide Metrology (ICRM) to evaluate the uncertainties involved in applying different analysis methodologies (including computer programs) for the triple-to-double coincidence ratio (TDCR) method. The goals of the comparison were to (1) study differences in calculation results from different TDCR analysis programs, (2) investigate differences in analysis techniques and uncertainty assessment philosophies between laboratories, and (3) study the effect of not taking asymmetry of photomultiplier tube (PMT) efficiencies into account on the calculated activity. To achieve this, a single set of TDCR data for the pure beta emitter (99)Tc, was distributed to the participants, who analyzed the data according to their normal procedures and report the activity concentration of the (99)Tc solution from their results. The results indicate that the presently used programs are generally able to calculate the same activity values, assuming that the correct input parameters are used and that not taking PMT asymmetry into account in the calculations can lead to significant (0.6% for (99)Tc) errors in reported results. The comparison also highlighted the need for a more rigorous approach to estimating and reporting uncertainties.

This paper summarizes the work done in the SARNET European Network of Excellence on Severe Accidents (6th Framework Programme of the European Commission) on the capability of the ASTEC code to simulate in-vessel corium retention (IVR). This code, jointly developed by the French Institut de Radioprotection et de Sûreté Nucléaire (IRSN) and the German Gesellschaft für Anlagen und Reaktorsicherheit mbH (GRS) for simulation of severe accidents, is now considered as the European reference simulation tool. First, the DIVA module of ASTEC code is briefly introduced. This module treats the core degradation and corium thermal behaviour, when relocated in the reactor lower head. Former ASTEC V1.2 version assumed a predefined stratified molten pool configuration with a metallic layer on the top of the volumetrically heated oxide pool. In order to reflect the results of the MASCA project, improved models that enable modelling of more general corium pool configurations were implemented by the CEA (France) into the DIVA module of the ASTEC V1.3 code. In parallel, the CEA was working on ASTEC modelling of the external reactor vessel cooling (ERVC). The capability of the ASTEC CESAR circuit thermal-hydraulics to simulate the ERVC was tested. The conclusions were that the CESAR module is capable of simulating this system although some numerical and physical instabilities can occur. Developments were then made on the coupling between both DIVA and CESAR modules in close collaboration with IRSN. In specific conditions, code oscillations remain and an analysis was made to reduce the numerical part of these oscillations. A comparison of CESAR results of the SULTAN experiments (CEA) showed an agreement on the pressure differences. The ASTEC V1.2 code version was applied to IVR simulation for VVER-440/V213 reactors assuming defined corium mass, composition and decay heat. The external cooling of reactor wall was simulated by applying imposed coolant temperature and heat transfer coefficient (HTC). The obtained results (pool temperatures, heat flux distribution, reactor wall ablation) were compared with available predictions of other codes. The agreement was correct, in particular on the shape and depth of ablation, as well as the maximum heat flux in case of a thick metallic layer, while ASTEC calculated a lower maximum heat flux for a thin metallic layer. © 2009 Elsevier B.V. All rights reserved.

The results of an international comparison of activity measurements of a solution of (55)Fe organized by the BIPM in 2005 are reported and analysed. This exercise, which follows the procedures of the CIPM mutual recognition arrangement to update older comparisons, is a renewal of the comparison organized by the BIPM that took place in 1978. A EUROMET comparison was organized in 1996 specifically to compare activity measurements of a (55)Fe solution by means of liquid-scintillation techniques. Results of these three comparisons are presented and discussed in this paper. The radionuclide solution was provided by the NPL, which also distributed the samples to the participants. The activity of the ampoules was measured by 16 laboratories using 12 methods producing 25 results. Some general considerations on uncertainty assessments pertaining to the different techniques used are drawn. The outcome of four different estimators is compared from which the presence of at least one outlier can be confirmed. Further measurements should be made to try to reduce the discrepancy between the results. To date the outcome of the present comparison does not show an improvement to that of the 1996 comparison.

Experimental results obtained on the Tokamak de Varennes during a series of reproducible ohmic discharges are presented. Profiles of basic plasma parameters are constructed and compared with theoretical predictions. In particular, the measured plasma resistivity agrees with the neoclassical scaling rather than with Spitzer resistivity. The study of electron-density fluctuations indicates a linear dispersion relation with a propagation velocity of 3.0 × 104 cm s−1. Particle transport investigations are initiated, giving experimental diffusion and convection coefficients across the plasma radius for electrons and impurity ions.

In 2008, the National Physical Laboratory (NPL) submitted one sample of known activity of 56Mn to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Mn-56. The value of the activity submitted was about 290 kBq. There is now one result in the BIPM.RI(II)-K1.Mn-56 comparison. The key comparison reference value (KCRV) has been evaluated for the first time using the NPL result and a BIPM result dating November 1978. The degree of equivalence between the NPL equivalent activity measured in the SIR and the KCRV has been calculated and is reported. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

A new participation in the BIPM.RI(II)-K1.Zn-65 comparison has been added to the previous results. A link has been made to the CCRI(II)-K2.Zn-65 comparison held in 2003 through the measurement of all ampoules of the K2 comparison in the International Reference System (SIR) at the BIPM before dispatch to the participants. This has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. Six NMIs used the K2 comparison to update their degrees of equivalence. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table for the remaining two NMIs in the BIPM.RI(II)-K1.Zn-65 comparison and the 17 other participants in the CCRI(II)-K2.Zn-65 comparison. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

In 2010, the Laboratoire National de M?trologie et d'Essais?Laboratoire National Henri Becquerel (LNE?LNHB) submitted one sample of known activity of 207Bi to the International Reference System for activity comparison at the Bureau International des Poids et Mesures, with comparison identifier BIPM.RI(II)-K1.Bi-207. The value of the activity submitted was about 180 kBq. There is now one result in the BIPM.RI(II)-K1.Bi-207 comparison. The key comparison reference value (KCRV) has been evaluated for the first time using the LNE?LNHB result and a PTB result dating 1982. The degree of equivalence between the LNE?LNHB equivalent activity measured in the SIR and the KCRV has been calculated and is reported. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The PTB submitted directly to the SIR one ampoule of 166mHo prepared from a dilution of the solution distributed to four laboratories participating in the EURAMET.RI(II)-K2.Ho-166m comparison in 2013. No attempt to evaluate a new KCRV has been made and the usual procedure was applied to link the results of the comparison to the usual SIR entries through the PTB. One NMI used this K2 comparison to update its previous degree of equivalence which is older than 20 years. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for the four remaining laboratories in the BIPM.RI(II)-K1.Ho166m comparison, the six laboratories in the regional comparison APMP.RI(II)-K2.Ho166m and the four laboratories in the regional EURAMET.RI(II)-K2.Ho-166m comparison. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Since 1975, ten laboratories have submitted 27 samples of known activity of 85Sr to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Sr-85. The values of the activity submitted were between about 0.2 MBq and 19 MBq. The key comparison reference value (KCRV) has been recalculated to include the primary standardization result for the POLATOM, Poland. There are now four results in the BIPM.RI(II)-K1.Sr-85 comparison. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Portability of the calibration of the ionisation chambers of the International Reference System, SIR, of the BIPM to other ionisation chambers used for activity measurements and without having direct access to SIR is described. A linear relationship between calibration figures of different ionisation chambers at IRMM, NPL and NAC and 1/ A e of SIR was established. In favourable cases uncertainties of the slope of less than 1% were obtained.