Nuclear Data: Fission Yields, Decay Heat and Neutron Reaction Cross Sections

The UK now has little capability in nuclear data measurement and evaluation despite the fact that these data are absolutely critical in underpinning many industrial nuclear applications. The nuclear industry in particular now faces a number of challenges connected with new nuclear build, plutonium disposition, and geological disposal. These areas rely on nuclear data codes which have served the UK well over the years but, due to compensating errors and correcting factors, are likely to depart from observation as the envelope of operation is extended into the new areas of application.This outline proposal will allow the UK to re-engage with international efforts to measure neutron absorption ad fission cross sections, fission yields, and gamma decay heat measurements at a number of European research facilities. This consortium will also help the analysis and evaluation work to ensure the nuclear industry in the UK benefits from the new measurements in a timely manner.The three strands of the proposed research programme are: (i) measurements of neutron capture cross sections on actinide targets through UK membership of the neutron Time-of-Flight collaboration working at CERN; (ii) Gamma decay heat measurements using a Total Absorption Spectrometer, and (iii) measurements of neutron-induced fission cross sections and fission yields using the UK's STEFF spectrometer at the SPIRAL2 pulsed neutron facility at GANIL (France).

The main impact of this proposal will be to create and foster networking and international opportunities. By joining nTOF the UK will be linked with one of the largest international networks for nuclear data measurements and evaluation. nTOF measurements contribute directly to the JEFF (Joint European Fission Fusion) and Brookhaven databases. The nTOF collaboration coordinates its measurements with IRMM (Geel, Belgium) to produce the best possible set of data. NNL involvement in this outline proposal via a recent Simon Fellowship appointment for Dr Mills at Manchester, and potentially an NNL-based research engineer (under the nuclear IDC scheme), will ensure the fastest possible uptake of new data by the nuclear industry. Membership of the nTOF collaboration opens the door to the creation of additional frameworks of collaborations, such as those funded by the EU. For example the nTOF spokesman is coordinator of the ANDES EURATOM FP7 project which already involves Manchester's long-time collaborator in JYFL (Jyvskyl IGISOL group) and the NNL nuclear physics group. Manchester has helped with the design and construction of the IGISOL target at the Jyvaskyla Accelerator Laboratory (JYFL). This facility is used for fission yield measurements, fission fragment mass measurements and fission fragment nuclear- and laser- spectroscopic studies. Manchester's research at this facility is already funded under a current EPSRC/STFC responsive mode grant and an STFC rolling grant, and now there is a good possibility to get involved with the ANDES project through working with JYFL. The UK forum for reporting and sharing information on nuclear data is the UK Nuclear Science Forum which is operated by NPL on behalf of HSE. The UKNSF advises representatives of the NEA database and the IAEA Nuclear Data Section on the needs of the UK in this field. Manchester and Surrey are already members of this forum. The NFS network has members from 18 institutions across Europe and has a large cohort or researchers with an interest in possible industrial applications. Manchester has good contacts already with the NFS working groups; the STEFF spectrometer forms part of the technical specification for the facility, even though there is currently no UK financial support for this involvement. Contact with data evaluators, e.g. Dr. Mills as well as future contacts formed through the nTOF collaboration, will allow the rapid dissemination of results of the NFS experiments to the nuclear industry. The Jyvskyl TAS work that the Surrey group (via Gelletly) has been seminal in the design and construction of the current TAS and Surrey will continue to have a large impact in the collaborations that use TAS. Nichols is Chair of the UK Nuclear Science Forum (UKNSF), which covers the measurement and evaluation of nuclear data for applications in the nuclear industry, nuclear medicine and protection of the environment. There are two meetings a year; and the association of Nichols with this consortium will increase the national impact of its work.