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Supplying Accurate Nuclear Data for energy and non-energy Applications

Periodic Reporting for period 1 - SANDA (Supplying Accurate Nuclear Data for energy and non-energy Applications)

Reporting period: 2019-09-01 to 2021-02-28

Nuclear data tools are a critical element of the nuclear energy industry and research, playing an essential role in the simulation of nuclear systems for nuclear energy and non-energy applications, for the assessment of safety and performance of reactors and for the use of radioactive materials in non-energy applications. No matter how sophisticated any tool is, no simulation or calculation can be better than the nuclear data they use. Several parameters, particularly safety parameters of reactors, need a precision < 0.1% resulting in nuclear data precisions of a few percent. In other cases the precision needed can range from 5 to 20% but the isotope or material to be measured is highly radioactive or scarce. So, despite decades of R&D, these precisions have still not been reached for all the isotopes and reactions required, raising important challenges. The tools and experiments being developed within SANDA, will bring at reach the target precision for some important isotopes/reactions. In addition, SANDA will contribute to prepare the path (new detectors, facilities and methods) for future experiments addressing the remaining nuclear data needs in the years to come.

The SANDA project puts together most of the European nuclear data community, and infrastructures to prepare the methodologies, detectors, facilities and tools to produce accurate and reliable nuclear data tools (data, codes and methods) that can be used to simulate, analyse and optimize the safety of nuclear energy and non-energy applications. The project is built taking into account the High Priority Nuclear Data needs list from OECD/NEA and IAEA.

SANDA includes 35 partners from 18 countries from EU plus Switzerland and the most relevant facilities to measure nuclear data. The participants of SANDA have been strongly involved in previous EURATOM projects and in international organizations dedicated to nuclear data (NEA/OECD and IAEA). SANDA also collaborates with the ARIEL project.

SANDA benefits from upgraded facilities and tools from previous EURATOM projects and uses newly developed detectors, methods and targets. SANDA also is developing and applying new evaluation and validation tools and associated integral experiments with special attention to the production and use of uncertainties and correlation matrices for experimental and evaluated data. The project covers the whole energy region for the needs of thermal and fast neutron reactors and non-energy applications, including the high energy data (up to few GeV) needed for the ADS and medical applications.

Special attention is given to use the research in SANDA for training of young scientists and engineers that will learn by doing during their PhD. Also, special care will be applied to the early and efficient dissemination of the project results to the EU community of nuclear data users.
During the first 18th months, SANDA, as proposed, has made most efforts and got achievements mainly on the developments of new innovative detector devices, differential measurements and target preparation, initiating also the work on data evaluation and validation with integral experiments.

Large achievements on new detectors for fission include the experimental validation of a new Gaseous Proton Recoil Telescope, the simulation and calibration of FALSTAFF-FIPPS (Milestone MS1), the design and test with sources of the new n-detector BRIKEN, the design and test of other neutron detectors (Stilbene, SCONE) and the test of the new facility for measurements of half-lives at CEA/DRT/LNE-LNHB. Also large progress has been made for gamma detectors including new electronics and test for HPGe at n_TOF, and the construction and tests of the sTED and validation of i-TED for n_TOF (EAR2). Attention is also being devoted to detectors for non-energy application (DDX data for the n-induced emission of lchp).

As for target preparation, a first set of samples has been identified and the preparation of these targets did already started. Additionally, the design and simulations of beam optics for the development of an isotope separator (IS) has been achieved and the preparation of the site for the IS at PSI have also started. This device will become a key element to allow important measurements once operative.

SANDA is also preparing and performing new nuclear data measurements including:
- data already taken and partly analysed at n_TOF for fission in 235U, 230Th, 241Am and 239Pu and nubar data taken at MONNET@JRC-Geel.
- in-beam tests and key detectors (MEDLEY) already moved to NFS to measure 16O(n,alpha) and natC(n,lchp) and other other (n,chp) reactions.
- construction of the fission tagging chamber for the 239Pu(n,g) and preparation of Mo(n,g) to be measured at GELINA and n_TOF.
- new data taking and analysis of 238U(n,inel) completed with an article in progress and new data taken for 233U(n,inel), 209Bi(n,g) and 209Bi(n,tot).
- improved analysis method with better results for decay data taken with DTAS detector with the publication of a Phys. Rev. C article.
- preparation of fission yields for 235U at ILL with LOHENGRIN and new methodology.
- for non-energy applications: data for dosimetry has been measured and analysed (117Sn(n,inl)117mSn) and measurement of production and analysis of long-lived beta+ emitters(11C and 13N) is also done.
For most of the other experiments proposed, the simulation and some tests with radioactive sources have already been done.

In parallel, large efforts are being applied to improve processing and sensitivity calculations that have already helped to improve JEFF3-3. Also, work for new evaluations is ongoing, already resulting on a new version of the GEF model. Furthermore, the identification of most relevant experimental benchmarks for validation with existing databases has already been achieved and validations are ongoing. Additionally, new integral experiments are being prepared at GELINA, MINERVE, LR-0 and TAPIRO, and although the actual experiments had to be postponed some months (COVID-19), progress has been made on their simulations.
The new detectors will improve performance on efficiency, sensitivity and resolution beyond the present state of the art.
There is provision of the production of a number of targets by PSI and JRC for measurements included within SANDA that will provide improved experimental conditions. The preparation for an isotope separator will have large impact on future experiments.
The measurements of SANDA will improve the precision of previous data, update data with few measurements and extend the energy and isotope ranges.
The new evaluations should provide better files and with covariance information for Cr, actinides (U235, U238, Pu239, and Am241), important fission products (Sm, Nd, Cs, Mo, Ru, Eu, Gd, Rh) and the Pu isotopic chain (Pu238-Pu244). Also new evaluations will improve the ENSDF JEFF libraries. An uncertainties model in high-energy models should also be covered.

With all these elements, the project is expected to contribute, directly and indirectly, to the enhancement of the safety and competitiveness of the European nuclear industry, also allowing to reduce operation and design margins, without sacrificing safety standards of present reactors, and in more competitive designs of new nuclear reactors and facilities. This enhancement of safety also will apply to the waste management, storage, reprocessing or disposal, and to the decommissioning of nuclear facilities.
SANDA Objectives