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Actinide, Activation Product and Fission Product Decay Data for Reactor-based Applications
Available online at www.sciencedirect.com
Nuclear Data Sheets 120 (2014) 261–263 www.elsevier.com/locate/nds
Actinide, Activation Product and Fission Product Decay Data for Reactor-based Applications R.J. Perry,1, ∗ C.J. Dean,1, † and A.L. Nichols2, 3 1
AMEC, Kimmeridge House, Dorset Green Technology Park, Winfrith Newburgh, Dorchester, Dorset, DT2 8ZB, UK 2 affiliated to the Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 7XH, UK 3 affiliated to Manipal University, Madhav Nagar, Manipal 576104, Karnataka, India The UK Activation Product Decay Data Library was first released in September 1977 as UKPADD1, to be followed by regular improvements on an almost yearly basis up to the assembly of UKPADD6.12 in March 2013. Similarly, the UK Heavy Element and Actinide Decay Data Library followed in December 1981 as UKHEDD1, with the implementation of various modifications leading to UKHEDD2.6, February 2008. Both the data content and evaluation procedures are defined, and the most recent evaluations are described in terms of specific radionuclides and the resulting consistency of their recommended decay-data files. New versions of the UKPADD and UKHEDD libraries are regularly submitted to the NEA Data Bank for possible inclusion in the JEFF library. I.
INTRODUCTION
The decay data of various radionuclides have been evaluated on the basis of a series of well-defined specifications. Activation products are of immediate relevance to the European Fusion Programme, while fission products, actinides and their decay products are extremely important in the operation and decommissioning of nuclear power facilities and disposal of all arising radioactive waste, along with the adoption of various standards for energy and efficiency calibration of gamma-ray spectrometers. Recommended decay-data parameters include half-lives, branching fractions, alpha, beta and gamma-ray energies and emission probabilities, total decay energies, mean electromagnetic, light-particle and heavy-particle energies, internal conversion coefficients, internal-pair formation coefficients, and all associated uncertainties. Computer based files have been generated as UKHEDD2.6 [1] and UKPADD6.12 [2], including lists of the references used to derive the proposed decay schemes and recommended decay data, and comments that describe the evaluation procedures in detail and identify any observed inadequacies. All of the evaluated data have been processed through the COGEND code [3] to yield complete and verified evaluated decay data files in ENDF-6 format. Various additional decay data were also calculated from the evaluated inputs by means of a series of sub-routines
∗ †
Corresponding author: [email protected] Deceased
http://dx.doi.org/10.1016/j.nds.2014.07.062 0090-3752/© 2014 Elsevier Inc. All rights reserved.
contained within COGEND, including X-rays, Auger and internal-conversion electrons. All evaluations for UKHEDD and UKPADD have been carried out by A.L. Nichols, while COGEND processing and verification were performed at Winfrith, UK. The evolving UKHEDD and UKPADD libraries have regularly been submitted to the NEA Data Bank for incorporation into the JEFF-3 library. II.
UKHEDD
The UK Heavy Element and Actinide Decay Data Library containing decay data for 125 radionuclides was initially released in 1981 as UKHEDD1. Subsequent improvements in specific features of the available decay data arose as a consequence of various laboratory studies, and resulted in comprehensive re-evaluations and the release of UKHEDD2 in 1991. Additional modifications have subsequently been carried out, leading up to 2008 with the most recent release of the UKHEDD2.6 library of decay data [1]. III.
UKPADD
Originally entitled the UK Activation Product Decay Data Library, UKPADD was first released in 1977 as UKPADD1, and contained recommended decay-data files for 91 radionuclides. However, improvements in the available decay data through various spectroscopic measurements led to a comprehensive evaluation of the decay data for 236 radionuclides. These improved data were released as UKPADD2 in 1993, and a large fraction of this particular
Actinide, Activation Product . . .
NUCLEAR DATA SHEETS
an evaluation, including experimental data from laboratory reports and private communications. Comprehensive statements of the precise evaluation procedure were prepared after each assessment, as well as details of any changes made to the reported data. Emission probabilities have been expressed as the absolute probability of the transition (α, β − , EC/β + , conversion electron, X-ray or γ ray) per decay. Every effort has been made to produce consistent and comprehensive data sets. When necessary, theoretical internal-conversion and internal-pair formation coefficients have been used in conjunction with the evaluated gamma-ray data to generate valid electron data. After the evaluation of a particular radionuclide has been completed, the recommended data are prepared by the evaluator and converted into a form suitable for input to the processing code COGEND [3]. This code derives various additional data (mean/average energies, discrete electrons, X-rays, etc.) from the evaluated input data using mathematical models and associated internal data libraries of fluorescence yields, Auger-electron energies, mean X-ray energies and electron-wave-function ratios to calculate the following parameters: 1. mean alpha, beta and gamma energies, 2. conversion-electron energies and emission probabilities, 3. K-, L- and M-shell capture ratios in electroncapture decay, 4. K-, L- and M-shell Auger-electron energies and emission probabilities, 5. K-, L- and M-shell X-ray energies and emission probabilities, 6. energy of recoil in alpha decay, 7. internal bremsstrahlung associated with beta decay. The component contributions to the mean energies (light particle, electromagnetic and heavy particle) are also derived from the evaluated input data by COGEND. All of the energy data are in eV, and the absolute emission probabilities are expressed as fractions of the decay (calculated from the spectral normalisation factor and relative emission probabilities). The evaluated decay data files produced by COGEND are applied to the standard ENDF utility codes STANEF and CHECKR to ensure adherence to the ENDF-6 format. The internal consistency of the files is also checked by means of an enhanced version of the FIZCON code [4].
decay-data library was incorporated into the Joint Evaluated File JEF-2.2. Subsequent decay-data reviews highlighted the need for further developments in the recommended data for fission and fusion applications. Hence, the contents of UKPADD were developed and expanded further over the 1990s, resulting in the release of UKPADD6 in 1999. Between 1999 and 2010, a programme of decay data evaluations was sponsored primarily by the UK Atomic Energy Authority (UKAEA) in support of the European Fusion Programme. While a significant number of the data files within the library are dedicated to activation products and related radionuclides, the recommended decay data for specific fission products have also been included as a consequence of convenience and the timing of a series of high-priority requests. The most recent version of the UKPADD library (UKPADD6.12) was released in April 2013, and contains files of evaluated decay data for 595 radionuclides [2]. IV.
R.J. Perry et al.
DECAY DATA - EVALUATION PROCEDURES
Both libraries have been generated in ENDF-6 format. Data contained in the information and comments section (MF = 1, MT = 451) for each nuclide comprise: 1. name of the evaluator and date of the evaluation (month and year), 2. list of references used to construct the recommended data set, 3. detailed comments associated with the evaluation, and 4. consistency check of the evaluated data. The recommended decay data for the following parameters are contained within the data section (MF = 8, MT = 457): • half-lives, • total decay energies (Q-values), • branching fractions (BFi ), • alpha-particle energies and emission probabilities, • beta-particle energies, emission probabilities and transition types, • β + /electron-capture (EC) transition energies, emission and transition probabilities, and transition types, • gamma-ray energies, emission probabilities, and internal-conversion and internal-pair formation coefficients, • neutron energies and emission probabilities, • spontaneous fission data including prompt gammaray spectra. The spin and parity of the decaying ground state of the nuclide are defined, and uncertainties assigned to all of the evaluated data. An initial decay scheme was constructed for each radionuclide from a suitable combination of the various data sources. Discrepancies were identified, and comprehensive decay schemes derived by means of a well-defined evaluation process. All available measurements were generally taken into account during
V.
RECENT EVALUATIONS, 2011/12 UKPADD6.12
Relatively complex decay schemes for several nuclides have been evaluated during the course of 2011/13 in response to postulated accident studies described in JEF/DOC-1291 [5]: 90 Kr, 90 Rb, 94 Sr, 136 I, 136m I, 139 Xe and 140 Cs. These radionuclides are important fission products that either contain no discrete spectral data in the existing JEFF evaluation (e.g. 139 Xe), or exhibit significant differences in the emitted gamma-ray dose be262
Actinide, Activation Product . . .
NUCLEAR DATA SHEETS
TABLE I. Evaluated files of discrete decay data - consistency check (ΔQ expressed as % deviation). Radionuclide Half-life (s) Decay properties 90 Kr 32.32(9) 87.2% β − (90 Rb) and 12.8% β − (90m Rb): 25β − /95γ (+7γ unplaced) 90 Rb 157(3) 100% β − : 26β − /88γ (+7γ unplaced) 94 Sr 75.3(2) 100% β − : 7β − /16γ 136 I 83.5(15) 100% β − : 51β − /116γ 136m I 47(1) 100% β − : 19β − /39γ 139 Xe 39.69(5) 100% β − : 64β − /271γ 140 Cs 64.0(5) 100% β − : 62β − /269γ
ΔQ(%) -0.3831
-0.6699 0.0312 -0.0093 -0.0482 0.1475 0.0062
tween JEF-2.2 and JEFF-3.1.1 (e.g. 90 Rb and 140 Cs). The resulting quality of the recommended decay data is based on the subjective judgement of the evaluator, aided by a consistency check of the proposed data set (Table I). Consistency within a recommended set of decay-scheme data was assessed by comparing the effective Q-value derived from the total decay energies (Qi ) and branching fractions (BFi ) all BFi Effective Q-value = Qi BFi , i=1
with the calculated Q-value determined from the summation of the energies of the individual decay processes (α, EC/β + , β − , γ, conversion electrons, etc.), expressed as the percentage deviation (ΔQ(%)). A value above 5% would be regarded as high and imply a poorly defined decay scheme, whereas less than 5% indicates the construction of a reasonably well-defined decay scheme. Evaluated β − and γ data have been predominantly derived from the discrete γ-ray measurements, as have the total mean beta and gamma energies for 90 Kr, 94 Sr, 136 I and 139 Xe. However, the total mean beta and gamma energies for 90 Rb and 140 Cs were determined from the TAGS studies of Greenwood et al. [6], while the total mean energies for 136m I were obtained from the gross beta-gamma spectral studies of Rudstam et al. [7]. Thus, the mean energies derived from the experimental studies of Greenwood et al. for 90 Rb and 140 Cs and Rudstam et al. for 136m I have replaced the equivalent data calculated from the discrete γ-ray studies in the mean energy data section located at the beginning of these particular ENDF-6 decay-data files. Mean antineutrino energies have also been re-calculated to maintain the overall en-
R.J. Perry et al.
ergy balance. These specific sets of component data are recommended for decay-heat calculations, while the mean gamma and beta data derived from the discrete spectra remain in the relevant sub-sections for use in radiation shielding studies.
VI.
CONCLUSIONS
Sets of recommended decay data have been derived for a series of radionuclides identified predominantly as (a) actinides and their decay products (UKHEDD2.6), and (b) activation products, a limited number of specific fission products, and calibrants (UKPADD6.12). The resulting evaluated data sets represent significant improvements in the quality of the derived decay parameters. Rigorous consistency checks have been undertaken to confirm the validity and completeness of the data before releasing the updated libraries in 2008 (as UKHEDD2.6) and 2013 (as UKPADD6.12). Comprehensive details of each evaluation can be found within the comments section of individual ENDF-6 files. The structure of all the evaluated files has also been updated to ensure that they are consistent with modern standards and can be assimilated into JEFF-3 and future libraries. Both databases are available via the NEA Data Bank, and all the decay data comprising UKHEDD2.6 and UKPADD6.12 have been submitted for possible inclusion in the evolving JEFF-3 Decay Data Library. Acknowledgements: JoAnn Totans (NNDC, BNL, USA) and Kira Nathani (IAEA-NDS, Vienna, Austria) have assisted greatly over recent years in the accumulation of the necessary and sometimes obscure references required to undertake the evaluations. The data evaluations, consistency checks and assembly of many of the earlier files were funded by BNFL plc, Sellafield, and the UK Department of Trade and Industry (work now identified with the UK Department of Energy and Climate Change), and Euratom through the UK Atomic Energy Authority/Euratom Fusion Association. Ray Perry and Alan Nichols would also like to pay tribute to Christopher Dean (UKAEA and Serco, Winfrith Newburgh, UK) for his significant input during the long-term discussions and preparation of technical arguments to justify the work described in this report, along with his support over the course of much of the evaluation work reported above, prior to his sad death in May 2012.
OECD Nuclear Energy Agency, Paris (2003). [5] C.J. Dean, G. Wright, R.J. Perry, JEF/DOC-1291, OECD Nuclear Energy Agency, Paris (2009). [6] R.C. Greenwood et al., Nucl. Instrum. Methods Phys. Res. A390, 95 (1997). [7] G. Rudstam, et al., At. Data Nucl. Data Tables 45, 239 (1990).
[1] A.L. Nichols, R.J. Perry, SERCO REPORT SERCO/TAS/000343/W002, Issue 1, Winfrith (2008). [2] A.L. Nichols, R.J. Perry, AMEC REPORT AMEC/TS/006301.10.01/002, Issue 1, Winfrith (2013). [3] R.J. Perry, C.J. Dean (originally A. Tobias), JEF/DOC1083, OECD Nuclear Energy Agency, Paris (2004). [4] R.J. Perry, M.J. Grimstone, C.J. Dean, JEF/DOC-959,
263
Nuclear Data Sheets 120 (2014) 261–263 www.elsevier.com/locate/nds
Actinide, Activation Product and Fission Product Decay Data for Reactor-based Applications R.J. Perry,1, ∗ C.J. Dean,1, † and A.L. Nichols2, 3 1
AMEC, Kimmeridge House, Dorset Green Technology Park, Winfrith Newburgh, Dorchester, Dorset, DT2 8ZB, UK 2 affiliated to the Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 7XH, UK 3 affiliated to Manipal University, Madhav Nagar, Manipal 576104, Karnataka, India The UK Activation Product Decay Data Library was first released in September 1977 as UKPADD1, to be followed by regular improvements on an almost yearly basis up to the assembly of UKPADD6.12 in March 2013. Similarly, the UK Heavy Element and Actinide Decay Data Library followed in December 1981 as UKHEDD1, with the implementation of various modifications leading to UKHEDD2.6, February 2008. Both the data content and evaluation procedures are defined, and the most recent evaluations are described in terms of specific radionuclides and the resulting consistency of their recommended decay-data files. New versions of the UKPADD and UKHEDD libraries are regularly submitted to the NEA Data Bank for possible inclusion in the JEFF library. I.
INTRODUCTION
The decay data of various radionuclides have been evaluated on the basis of a series of well-defined specifications. Activation products are of immediate relevance to the European Fusion Programme, while fission products, actinides and their decay products are extremely important in the operation and decommissioning of nuclear power facilities and disposal of all arising radioactive waste, along with the adoption of various standards for energy and efficiency calibration of gamma-ray spectrometers. Recommended decay-data parameters include half-lives, branching fractions, alpha, beta and gamma-ray energies and emission probabilities, total decay energies, mean electromagnetic, light-particle and heavy-particle energies, internal conversion coefficients, internal-pair formation coefficients, and all associated uncertainties. Computer based files have been generated as UKHEDD2.6 [1] and UKPADD6.12 [2], including lists of the references used to derive the proposed decay schemes and recommended decay data, and comments that describe the evaluation procedures in detail and identify any observed inadequacies. All of the evaluated data have been processed through the COGEND code [3] to yield complete and verified evaluated decay data files in ENDF-6 format. Various additional decay data were also calculated from the evaluated inputs by means of a series of sub-routines
∗ †
Corresponding author: [email protected] Deceased
http://dx.doi.org/10.1016/j.nds.2014.07.062 0090-3752/© 2014 Elsevier Inc. All rights reserved.
contained within COGEND, including X-rays, Auger and internal-conversion electrons. All evaluations for UKHEDD and UKPADD have been carried out by A.L. Nichols, while COGEND processing and verification were performed at Winfrith, UK. The evolving UKHEDD and UKPADD libraries have regularly been submitted to the NEA Data Bank for incorporation into the JEFF-3 library. II.
UKHEDD
The UK Heavy Element and Actinide Decay Data Library containing decay data for 125 radionuclides was initially released in 1981 as UKHEDD1. Subsequent improvements in specific features of the available decay data arose as a consequence of various laboratory studies, and resulted in comprehensive re-evaluations and the release of UKHEDD2 in 1991. Additional modifications have subsequently been carried out, leading up to 2008 with the most recent release of the UKHEDD2.6 library of decay data [1]. III.
UKPADD
Originally entitled the UK Activation Product Decay Data Library, UKPADD was first released in 1977 as UKPADD1, and contained recommended decay-data files for 91 radionuclides. However, improvements in the available decay data through various spectroscopic measurements led to a comprehensive evaluation of the decay data for 236 radionuclides. These improved data were released as UKPADD2 in 1993, and a large fraction of this particular
Actinide, Activation Product . . .
NUCLEAR DATA SHEETS
an evaluation, including experimental data from laboratory reports and private communications. Comprehensive statements of the precise evaluation procedure were prepared after each assessment, as well as details of any changes made to the reported data. Emission probabilities have been expressed as the absolute probability of the transition (α, β − , EC/β + , conversion electron, X-ray or γ ray) per decay. Every effort has been made to produce consistent and comprehensive data sets. When necessary, theoretical internal-conversion and internal-pair formation coefficients have been used in conjunction with the evaluated gamma-ray data to generate valid electron data. After the evaluation of a particular radionuclide has been completed, the recommended data are prepared by the evaluator and converted into a form suitable for input to the processing code COGEND [3]. This code derives various additional data (mean/average energies, discrete electrons, X-rays, etc.) from the evaluated input data using mathematical models and associated internal data libraries of fluorescence yields, Auger-electron energies, mean X-ray energies and electron-wave-function ratios to calculate the following parameters: 1. mean alpha, beta and gamma energies, 2. conversion-electron energies and emission probabilities, 3. K-, L- and M-shell capture ratios in electroncapture decay, 4. K-, L- and M-shell Auger-electron energies and emission probabilities, 5. K-, L- and M-shell X-ray energies and emission probabilities, 6. energy of recoil in alpha decay, 7. internal bremsstrahlung associated with beta decay. The component contributions to the mean energies (light particle, electromagnetic and heavy particle) are also derived from the evaluated input data by COGEND. All of the energy data are in eV, and the absolute emission probabilities are expressed as fractions of the decay (calculated from the spectral normalisation factor and relative emission probabilities). The evaluated decay data files produced by COGEND are applied to the standard ENDF utility codes STANEF and CHECKR to ensure adherence to the ENDF-6 format. The internal consistency of the files is also checked by means of an enhanced version of the FIZCON code [4].
decay-data library was incorporated into the Joint Evaluated File JEF-2.2. Subsequent decay-data reviews highlighted the need for further developments in the recommended data for fission and fusion applications. Hence, the contents of UKPADD were developed and expanded further over the 1990s, resulting in the release of UKPADD6 in 1999. Between 1999 and 2010, a programme of decay data evaluations was sponsored primarily by the UK Atomic Energy Authority (UKAEA) in support of the European Fusion Programme. While a significant number of the data files within the library are dedicated to activation products and related radionuclides, the recommended decay data for specific fission products have also been included as a consequence of convenience and the timing of a series of high-priority requests. The most recent version of the UKPADD library (UKPADD6.12) was released in April 2013, and contains files of evaluated decay data for 595 radionuclides [2]. IV.
R.J. Perry et al.
DECAY DATA - EVALUATION PROCEDURES
Both libraries have been generated in ENDF-6 format. Data contained in the information and comments section (MF = 1, MT = 451) for each nuclide comprise: 1. name of the evaluator and date of the evaluation (month and year), 2. list of references used to construct the recommended data set, 3. detailed comments associated with the evaluation, and 4. consistency check of the evaluated data. The recommended decay data for the following parameters are contained within the data section (MF = 8, MT = 457): • half-lives, • total decay energies (Q-values), • branching fractions (BFi ), • alpha-particle energies and emission probabilities, • beta-particle energies, emission probabilities and transition types, • β + /electron-capture (EC) transition energies, emission and transition probabilities, and transition types, • gamma-ray energies, emission probabilities, and internal-conversion and internal-pair formation coefficients, • neutron energies and emission probabilities, • spontaneous fission data including prompt gammaray spectra. The spin and parity of the decaying ground state of the nuclide are defined, and uncertainties assigned to all of the evaluated data. An initial decay scheme was constructed for each radionuclide from a suitable combination of the various data sources. Discrepancies were identified, and comprehensive decay schemes derived by means of a well-defined evaluation process. All available measurements were generally taken into account during
V.
RECENT EVALUATIONS, 2011/12 UKPADD6.12
Relatively complex decay schemes for several nuclides have been evaluated during the course of 2011/13 in response to postulated accident studies described in JEF/DOC-1291 [5]: 90 Kr, 90 Rb, 94 Sr, 136 I, 136m I, 139 Xe and 140 Cs. These radionuclides are important fission products that either contain no discrete spectral data in the existing JEFF evaluation (e.g. 139 Xe), or exhibit significant differences in the emitted gamma-ray dose be262
Actinide, Activation Product . . .
NUCLEAR DATA SHEETS
TABLE I. Evaluated files of discrete decay data - consistency check (ΔQ expressed as % deviation). Radionuclide Half-life (s) Decay properties 90 Kr 32.32(9) 87.2% β − (90 Rb) and 12.8% β − (90m Rb): 25β − /95γ (+7γ unplaced) 90 Rb 157(3) 100% β − : 26β − /88γ (+7γ unplaced) 94 Sr 75.3(2) 100% β − : 7β − /16γ 136 I 83.5(15) 100% β − : 51β − /116γ 136m I 47(1) 100% β − : 19β − /39γ 139 Xe 39.69(5) 100% β − : 64β − /271γ 140 Cs 64.0(5) 100% β − : 62β − /269γ
ΔQ(%) -0.3831
-0.6699 0.0312 -0.0093 -0.0482 0.1475 0.0062
tween JEF-2.2 and JEFF-3.1.1 (e.g. 90 Rb and 140 Cs). The resulting quality of the recommended decay data is based on the subjective judgement of the evaluator, aided by a consistency check of the proposed data set (Table I). Consistency within a recommended set of decay-scheme data was assessed by comparing the effective Q-value derived from the total decay energies (Qi ) and branching fractions (BFi ) all BFi Effective Q-value = Qi BFi , i=1
with the calculated Q-value determined from the summation of the energies of the individual decay processes (α, EC/β + , β − , γ, conversion electrons, etc.), expressed as the percentage deviation (ΔQ(%)). A value above 5% would be regarded as high and imply a poorly defined decay scheme, whereas less than 5% indicates the construction of a reasonably well-defined decay scheme. Evaluated β − and γ data have been predominantly derived from the discrete γ-ray measurements, as have the total mean beta and gamma energies for 90 Kr, 94 Sr, 136 I and 139 Xe. However, the total mean beta and gamma energies for 90 Rb and 140 Cs were determined from the TAGS studies of Greenwood et al. [6], while the total mean energies for 136m I were obtained from the gross beta-gamma spectral studies of Rudstam et al. [7]. Thus, the mean energies derived from the experimental studies of Greenwood et al. for 90 Rb and 140 Cs and Rudstam et al. for 136m I have replaced the equivalent data calculated from the discrete γ-ray studies in the mean energy data section located at the beginning of these particular ENDF-6 decay-data files. Mean antineutrino energies have also been re-calculated to maintain the overall en-
R.J. Perry et al.
ergy balance. These specific sets of component data are recommended for decay-heat calculations, while the mean gamma and beta data derived from the discrete spectra remain in the relevant sub-sections for use in radiation shielding studies.
VI.
CONCLUSIONS
Sets of recommended decay data have been derived for a series of radionuclides identified predominantly as (a) actinides and their decay products (UKHEDD2.6), and (b) activation products, a limited number of specific fission products, and calibrants (UKPADD6.12). The resulting evaluated data sets represent significant improvements in the quality of the derived decay parameters. Rigorous consistency checks have been undertaken to confirm the validity and completeness of the data before releasing the updated libraries in 2008 (as UKHEDD2.6) and 2013 (as UKPADD6.12). Comprehensive details of each evaluation can be found within the comments section of individual ENDF-6 files. The structure of all the evaluated files has also been updated to ensure that they are consistent with modern standards and can be assimilated into JEFF-3 and future libraries. Both databases are available via the NEA Data Bank, and all the decay data comprising UKHEDD2.6 and UKPADD6.12 have been submitted for possible inclusion in the evolving JEFF-3 Decay Data Library. Acknowledgements: JoAnn Totans (NNDC, BNL, USA) and Kira Nathani (IAEA-NDS, Vienna, Austria) have assisted greatly over recent years in the accumulation of the necessary and sometimes obscure references required to undertake the evaluations. The data evaluations, consistency checks and assembly of many of the earlier files were funded by BNFL plc, Sellafield, and the UK Department of Trade and Industry (work now identified with the UK Department of Energy and Climate Change), and Euratom through the UK Atomic Energy Authority/Euratom Fusion Association. Ray Perry and Alan Nichols would also like to pay tribute to Christopher Dean (UKAEA and Serco, Winfrith Newburgh, UK) for his significant input during the long-term discussions and preparation of technical arguments to justify the work described in this report, along with his support over the course of much of the evaluation work reported above, prior to his sad death in May 2012.
OECD Nuclear Energy Agency, Paris (2003). [5] C.J. Dean, G. Wright, R.J. Perry, JEF/DOC-1291, OECD Nuclear Energy Agency, Paris (2009). [6] R.C. Greenwood et al., Nucl. Instrum. Methods Phys. Res. A390, 95 (1997). [7] G. Rudstam, et al., At. Data Nucl. Data Tables 45, 239 (1990).
[1] A.L. Nichols, R.J. Perry, SERCO REPORT SERCO/TAS/000343/W002, Issue 1, Winfrith (2008). [2] A.L. Nichols, R.J. Perry, AMEC REPORT AMEC/TS/006301.10.01/002, Issue 1, Winfrith (2013). [3] R.J. Perry, C.J. Dean (originally A. Tobias), JEF/DOC1083, OECD Nuclear Energy Agency, Paris (2004). [4] R.J. Perry, M.J. Grimstone, C.J. Dean, JEF/DOC-959,
263