HPRL -- International cooperation to identify and monitor priority nuclear data needs for nuclear applications
E. Dupont, M. Bossant, R. Capote, A.D. Carlson, Y. Danon, M. Fleming, Z. Ge, H. Harada, O. Iwamoto, N. Iwamoto, A. Kimura, A.J. Koning, C. Massimi, A. Negret, G. Noguere, A. Plompen, V. Pronyaev, G. Rimpault, S. Simakov, A. Stankovskiy, W. Sun, A. Trkov, H. Wu, K. Yokoyama
aa r X i v : . [ nu c l - e x ] A p r HPRL – International cooperation to identify and monitor priority nuclear dataneeds for nuclear applications E. Dupont , M. Bossant , R. Capote , A.D.
Carlson , Y. Danon , M. Fleming , Z. Ge , H. Harada , O. Iwamoto , N. Iwamoto , A. Kimura , A.J.
Koning , C. Massimi , A. Negret , G. Noguere , A. Plompen , V. Pronyaev , G. Rimpault , S. Simakov , A. Stankovskiy , W. Sun , A. Trkov , H. Wu , K. Yokoyama , and the NEA WPECExpert Group on the High Priority Request List for Nuclear Data , ∗ CEA, Irfu, Universite Paris-Saclay, Gif-sur-Yvette, France OECD, Nuclear Energy Agency (NEA), Boulogne-Billancourt, France IAEA, NAPC Nuclear Data Section (NDS), Vienna, Austria National Institute of Standards and Technology (NIST), Gaithersburg, MD, USA Rensselaer Polytechnic Institute (RPI), Troy, NY, USA CIAE, China Nuclear Data Center (CNDC), Beijing, China Japan Atomic Energy Agency (JAEA), Tokai-mura, Japan Istituto Nazionale di Fisica Nucleare (INFN) & University of Bologna, Bologna, Italy “Horia Hulubei” National Institute for Physics and Nuclear Engineering (IFIN-HH), Bucharest - Magurele, Romania CEA, Nuclear Energy Division (DEN), Cadarache, France European Commission, Joint Research Centre, Geel, Belgium Contractor, NAPC Nuclear Data Section (NDS), IAEA, Vienna, Austria Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany SCK-CEN, Mol, Belgium Institute of Applied Physics and Computational Mathematics (IAPCM), Beijing, China / science / wpec / hprl Abstract.
The OECD-NEA High Priority Request List (HPRL) is a point of reference to guide and stimulatethe improvement of nuclear data for nuclear energy and other applications, and a tool to bridge the gap betweendata users and producers. The HPRL is application-driven and the requests are submitted by nuclear data usersor representatives of the user’s communities. A panel of international experts reviews and monitors the requestsin the framework of an Expert Group mandated by the NEA Nuclear Science Committee Working Party onInternational Nuclear Data Evaluation Cooperation (WPEC). After approval, individual requests are classifiedto three categories: high priority requests, general requests, and special purpose requests (e.g., dosimetry,standards). The HPRL is hosted by the NEA in the form of a relational database publicly available on theweb. This paper provides an overview of HPRL entries, status and outlook. Examples of requests successfullycompleted are given and new requests are described with emphasis on updated nuclear data needs in the fieldsof nuclear energy, neutron standards and dosimetry.
The High Priority Request List (HPRL) for nuclear datahas been established under the auspices of the Nuclear En-ergy Agency (NEA) in the 80s. The list is a compilationof the highest priority nuclear data requirements from nu-clear data users. The purpose is to stimulate and guidemeasurement, nuclear theory and evaluation programmes.The rationale for the current list was established in the2000s [1, 2] on the basis of more stringent criteria foradopting new requests. The list provides an internationalpoint of reference for both nuclear data users and produc-ers, and its e ff ectiveness in stimulating new measurements,evaluations and verification actions to meet the needs iswell established. ∗ e-mail: [email protected] The HPRL is managed by an Expert Group mandated bythe NEA Working Party on International Nuclear DataEvaluation Cooperation (WPEC) working in close col-laboration with NEA for administrative items and for themaintenance of the HPRL database, tools and web pages.
A standing Expert Group is essential to maintain theHPRL as a point of reference in nuclear data research anddevelopment. The Expert Group consists of representa-tives from data evaluation project with expertise in thefields of nuclear data validation, evaluation and measure-ments. The Expert Group is responsible for managing thectivities related to the HPRL, in particular for guarantee-ing that the entries are up-to-date and well-motivated bycurrent interests in the field of nuclear energy and othernuclear applications. The Expert Group is also responsi-ble for stimulating follow-up to the entries and collectingthe feedback provided by any of the related activities thatmay follow in response of a request.
The HPRL is driven by nuclear applications on the basisof requests for specific nuclear data improvement made byusers. All requests should be well justified in terms of im-pact on the application and of accuracy requirement withrespect to the state-of-the-art experimental and evaluateddata.The HPRL consists of a list with high priority requests,a list with general requests and a list with special purposerequests divided in categories. Stringent criteria are ap-plied for entries on the lists. These are evaluated by theExpert Group that makes the final decision for adopting arequest in one of the lists. • A “high priority” request is justified by sensitivity stud-ies (or equivalent) and su ffi ciently documented. • A “general” request is well motivated for a specificquantity on a specific nucleus and is documented, butlacks a detailed backing by a sensitivity analysis or animpact study. • A “special purpose quantity” (SPQ) request in a well-defined category is of interest to a recognised importantfield of applied nuclear science for which it is essentialto stimulate new activity.The HPRL is subject to periodic review to monitorprogress and assess the status of each entry. This is re-flected by one of the following status: • “Work in progress” for entries with ongoing experimen-tal and theoretical activities. • “Pending new evaluation or validation” for entries thathave already stimulated a lot of activities, but are notcompleted yet because of the lack of new evaluation orvalidation. • “Completed” (or “Archived”) for entries that have beensatisfied (or that are no longer relevant as priority need).For the latter status the decision to terminate a requestrequires a consensus among the experts and care is takennot to a ff ect too strongly the related activities. The HPRL database, tools and web pages [3] are hostedand maintained by the NEA. The technical implementa-tion of the HPRL tools relies on Perl scripts connected toan Oracle relational database on the back and to HTMLweb pages on the front. They provide both a direct accessto the request lists and to a search interface for queryingthe database, as well as to an online form for submitting anew request. The latter should contain various information on the requested improvement, the most important beingthe impact on the application, the accuracy requested onthe nuclear data, and the justification with respect to thecurrent state-of-the-art.
The content of the database is summarized in table 1 withrespect to categories and status. Although the “Work inprogress” status dominates over the “Completed” entries,a sustained and continuous e ff ort is currently dedicated foreach of these entries. More information on the related ac-tivities is available in the HPRL web pages [3]. The fol-lowing subsections and tables give an overview of the nu-clear data improvements requested. The requests for fission and capture cross sections relevantto nuclear reactors are listed in table 2.Requests for improvement of fission cross sectionsconcern minor actinides (Np, Pu, Am, and Cm isotopes).With the exception of the request to improve the Np-237fission, which is now completed, other requests are stillwork in progress after they have been put forward byWPEC Subgroup 26 (SG-26) [4].The requests for capture cross sections concern majoractinides, such as the Big-3 (U-235,238 and Pu-239) andtwo other important fissile actinides (U-233, Pu-241), aswell as two minor actinides (Pu-242, Am-241). These re-quests had also been put forward by SG-26. Additionalrecent capture requests concern structural material (minorisotopes of Cr [5]) and neutron absorbers (Gd-155,157 [6]and Hf-nat). A significant achievement is the fulfilment ofthe requests for U-235 and U-238 capture cross sections,which were the subject of intensive collaborative works inthe framework of the CIELO project [7, 8].The requests for other partial cross sections are com-piled in table 3. Part of these requests had been submit-ted by SG-26, they concern inelastic scattering reactionon U-238, structural materials (Fe-56 and Si-28, whichis now completed), and coolant of fast reactors (Na-23,Pb-206,207). There is also a recent request to improvethe knowledge of the Bi-209 capture branching ratio (br)leading to the production of Po-210 in Pb-Bi eutectic un-der irradiation [9]. The remaining active requests are forK-39 activation and gas production cross sections in theNaK coolant of IFMIF-DONES [10] and for needs re-lated to neutron transport and criticality-safety (O-16, Pu-239 [11]).The HPRL is not limited to cross sections and table 4shows requests for other quantities such as angular distri-butions, spectra and nubar. Improvement is requested forthe H-2(n,el) energy-angle scattering probability distribu-tion. There are also requests to improve the accuracy ofimportant fission quantities, such as the Prompt FissionGamma Spectra (PFGS) of the U-235 and Pu-239 majoractinides, as well as the Prompt Fission Neutron Spectra(PFNS) of Am-243 and Cm-244 minor actinides, and alsothe nubar of U-233 and Pu-239,240. able 1.
Number of requests vs. categories and status. The values between parentheses are for individual requests in the SPQ category.
Status & categories High priority General Special Purpose Quantity TotalWork in progress 26 6 5 (64) 37 (96)Pending new evaluation or validation 4 0 0 4Completed 4 4 0 8Total 34 10 5 (64) 49 (108)
Table 2.
Fission and capture cross section requests relevant to nuclear reactors
Nuclide Reaction Half-life Energy range Nuclide Reaction Half-life Energy rangeNp-237 ∗ (n,f) 2.1 My 200 keV-20 MeV U-233 (n, γ ) 159 ky Thermal-1 MeVPu-238 (n,f) 88 y 9 keV-6 MeV U-235 ∗ (n, γ ) 704 My 100 eV-1 MeVPu-240 (n,f) 6.6 ky 0.5 keV-5 MeV U-238 ∗ (n, γ ) ∼ stable 20 eV-25 keVPu-241 (n,f) 14 y 0.5 eV-1.35 MeV Pu-239 (n, γ ) 24 ky 1 meV-1.35 MeVPu-242 (n,f) 375 ky 200 keV-20 MeV Pu-241 (n, γ ) 14 y 0.1 eV-1.35 MeVAm-241 (n,f) 432 y 180 keV-20 MeV Pu-242 (n, γ ),(n,tot) 375 ky 0.5 eV-2 keVAm-242m (n,f) 141 y 0.5 keV-6 MeV Am-241 (n, γ ),(n,tot) 432 y Thermal-FastCm-244 (n,f) 18 y 65 keV-6 MeV Cr-50,53 † (n, γ ) stable 1 keV-100 keVCm-245 (n,f) 8.5 ky 0.5 keV-6 MeV Gd-155,157 † (n, γ ),(n,tot) stable Thermal-100 eVHf-nat ∗ (n, γ ) stable 0.5 eV-5 keV ∗ Request completed † Recent request ( ≥ Table 3.
Other partial cross section requests in various fields
Nuclide Reaction Energy rangeU-238 (n,inl) 65 keV-20 MeVFe-56 (n,inl) 0.5 MeV-20 MeVSi-28 ∗ (n,inl) 1.4 MeV-6 MeVNa-23 (n,inl) 0.5 MeV-1.3 MeVPb-206,207 (n,inl) 0.5 MeV-6 MeVBi-209 † (n, γ ) br 500 eV-300 keVSi-28 ∗ (n,np) Threshold-20 MeVK-39 † (n,p),(n,np) 10 MeV-20 MeVCr-52 ∗ (n,xd),(n,xt) Threshold-65 MeVO-16 (n,a) 2 MeV-20 MeVPu-239 † (n,tot) 1st resonanceAu-197 ∗ (n,tot) 5 keV-200 keV ∗ Request completed † Recent request ( ≥ Table 4.
Requests for other various quantities
Nuclide Reaction Quantity Energy rangeH-2 (n,el) d / d θ ∗ (n,xn) DDX 7 MeV-20 MeVU-235 (n,f) γ spectrum Thermal-FastPu-239 (n,f) γ spectrum Thermal-FastAm-243 (n,f) n spectrum Thermal-10 MeVCm-244 (n,f) n spectrum Thermal-10 MeVU-233 (n,f) nubar Thermal-10 keVPu-239 † (n,f) nubar Thermal-5 eVPu-240 (n,f) nubar 200 keV-2 MeV ∗ Request completed † Recent request ( ≥ The category of Special Purpose Quantity was introducedin 2014 for requests individually lacking justifications tobe accepted in the High priority or General categories, butwith obvious generic value in a well-defined field. As oftoday, requests have been received in the fields of stan- dards and dosimetry. A new subcategory dedicated tomedical applications is foreseen.
In the SPQ subcategory dedicated to standards, requestshave been received to further improve the n-p primarystandard and to extend the fission standard at higher en-ergy [12] (see table 5).
Table 5.
Requests for improvement of standards
Nuclide Reaction Quantity Energy rangeH-1 (n,el) xs, d / d θ † (n,f),(p,f) xs 100-500 MeV † Recent request ( ≥ In the SPQ subcategory dedicated to dosimetry, recent re-quests have been adopted to address three di ff erent needs.The first one is related to IRDFF validation [13, 14],which requires measurements of a number of spectrum-averaged cross sections (SACS) in well characterized Cf-252(sf) and / or U-235(n th ,f) neutron fields (see table 6).The second one is for improvement of the high-energytail of the Pu-239(n th ,f) PFNS that requires measurementsof spectrum-averaged cross sections in a well charac-terised Pu-239 PFNS field [15]. The SACS should be mea-sured for well-known high-threshold dosimetry (n,2n) re-actions on F-19, Mn-55, Co-59, Ni-58, As-75, Y-89, Zr-90, Nb-93, I-127 and Tm-169.The third and last one concerns the dosimetry ofneutron sources that requires the measurement of bothlow-threshold, Sn-117(n,inl), and high-threshold crosssections with plateaus located between ≈
15 MeV and ≈
150 MeV [13, 14] (see table 7). able 6.
Recent requests for spectrum-averaged cross sections relevant for the improvement and validation of IRDFF
Nuclide Reaction Spectra ‡ Nuclide Reaction Spectra ‡ Nuclide Reaction Spectra ‡ Co-59 (n, γ ) Cf Rh-103 (n,inl)Rh-103m U5 Al-27 (n,2n) Cf & U5Th-232 (n,f) Cf Tm-169 (n,2n) U5 Ti-46 (n,2n) Cf & U5Zn-67 (n,p) Cf Cu-65 (n,2n) U5 Sn-117 (n,inl)Sn-117m Cf & U5Mo-92 (n,p)Nb-92m Cf Mn-55 (n,2n) U5 Ti-47 (n,np) Cf & U5Ni-60 (n,p) Cf Ni-58 (n,2n) U5 Ti-48 (n,np) Cf & U5Fe-54 (n,a) Cf Am-241 (n,f) Cf & U5 Ti-49 (n,np) Cf & U5As-75 (n,2n) Cf P-31 (n,p) Cf & U5 Fe-54 (n,2n) Cf & U5Y-89 (n,2n) Cf U-238 (n,2n) Cf & U5 Tm-169 (n,3n) Cf & U5Mn-55 (n, γ ) U5 In-115 (n,2n)In-114m Cf & U5 Bi-209 (n,3n) Cf & U5U-238 (n, γ ) U5 Pr-141 (n,2n) Cf & U5 Co-59 (n,3n) Cf & U5Cu-63 (n, γ ) U5 Cr-52 (n,2n) Cf & U5La-139 (n, γ ) U5 Na-23 (n,2n) Cf & U5 ‡ Cf and U5 stand for PFNS of Cf-252(sf) and U-235(n th ,f), respectively Table 7.
Recent requests for improvement of cross sections relevant to the dosimetry of neutron sources
Nuclide Reaction Energy range (MeV) Nuclide Reaction Energy range (MeV)Sn-117 (n,inl)Sn-117m 5 - 10 Cu-63 (n,2n) 20 - 100Fe-nat (n,x)Mn-54 15 - 100 Fe-54 (n,2n) 15 - 100Y-89 (n,p) 15 - 100 Au-197 (n,xn) x = / Threshold - 100Y-89 (n,xn) x = / Threshold - 100 Tm-169 (n,xn) x = = / Threshold - 150Ti-nat (n,x)Sc-47 15 - 100 Co-59 (n,xn) x = / Threshold - 150Ti-nat (n,x)Sc-48 15 - 100 Rh-103 (n,xn) x = = / Threshold - 100 La-139 (n,xn) x = = / Threshold - 100
In order to e ffi ciently stimulate and guide nuclear data im-provement the HPRL follows a twofold strategy. First ofall, the HPRL aims to be a reference tool in support toexperimental, theoretical and evaluation projects aimingat improving nuclear data. In parallel, the HPRL aims tobridge the gap between nuclear data users and nuclear dataproducers (evaluators and experimentalists).The role of the NEA WPEC Expert Group in close col-laboration with the nuclear data community is to ensurethat the HPRL is up-to-date and properly reflecting thepriority needs in the field of nuclear energy and other nu-clear applications, as well as advances aiming at answer-ing those needs.Nuclear data users are invited to contribute with newrequests either by email or using the online form [3]. Feed-back on HPRL entries from both users and producers ofnuclear data is obviously welcome. References [1] D. Smith, et al. , ND2004, Santa Fe, NM, USA, 26Sep. - 1 Oct. 2004, AIP Conf. Proc. , 545 (2005);https: // doi.org / / et al. , ND2007, Nice, France, April 22-27, 2007, EDP Sciences Proceedings, page 765 (2007);https: // doi.org / / / dbdata / hprl[4] M. Salvatores, et al. , Report NEA / / science / wpec[5] V. Koscheev, et al. , EPJ Conf. , 06025 (2017);https: // doi.org / / epjconf / et al. , Annals of Nuclear Energy , 537(2019); https: // doi.org / / j.anucene.2019.06.025[7] M. Chadwick, et al. , Nuclear Data Sheets , 189(2018); https: // doi.org / / j.nds.2018.02.003[8] R. Capote, et al. , Nuclear Data Sheets , 254(2018); https: // doi.org / / j.nds.2018.02.005[9] L. Fiorito, et al. , EPJ Nucl. Sci. Technol. , 48 (2018);https: // doi.org / / epjn / et al. / dbdata / je ff [11] C. De Saint Jean, et al. , Report NEA / / science / wpec[12] A.D. Carlson, et al. , Nuclear Data Sheets , 143(2018); https: // doi.org / / j.nds.2018.02.002[13] A. Trkov, et al. , INDC(NDS)-0639 (2013);https: // / publications / indc / indc-nds-0639[14] S. Simakov, et al. , Proposals for new measurements(2017); https: // / IRDFFtest[15] R. Capote, et al. , Nuclear Data Sheets , 1 (2016);https: // doi.org / //