Traceability of Neutron Cross Sections, Measurements, and Detector Development
MPD E.5.0: TRACEABILITY OF NEUTRON CROSS SECTIONS, MEASUREMENTS, AND DETECTOR DEVELOPMENT
Objective: Develop a coherent metrology program to meet the diverse and numerous demands of Department of Energy’s Advanced Fuel Cycle Initiative involving a plurality of isotopes in conjunction with DOE and university laboratories.
Background: To advance the US transition to a greater use of nuclear power, the Department of Energy (DOE) is engaged in an Advanced Fuel Cycle Initiative (AFCI). This initiative is focused on the development of more cost-effective use of fast reactors. The database on pertinent nuclear reactions requires up-dating and input based upon the best-available detection equipment. Such input data is needed to facilitate and anticipate life-cycle issues that may occur with such fast reactors. Within the AFCI, a cross-agency group was formed, the Nuclear Physics Working Group (NPWG), to be a forum amongst various stakeholders for the sharing of pertinent information. Generated data must be analyzed for its covariance, sensitivity and uncertainties for it to be most useful. Within the AFCI, there are several sub-topics being addressed, these are sometimes called “campaigns.”
The specific sub-topics or “campaigns,” which will benefit from enhanced nuclear data, are:
The Fast Reactor Research and Development Campaign The Safeguards Campaign The Systems Integration Campaign The Modeling and Simulation Campaign The Fuels Campaign
Another area of concern is Criticality Safety. Specific sub-sets of data needs for fast reactors require research into fission measurements, research into capture measurements, research into the elastic/inelastic components in interpreting and analyzing measurements, research into the fission neutron spectrum measurements as well as an underlying support for basic nuclear physics.
The kinds of data that need to be generated on a broad plurality of isotopes, some of more interest than others to the defined sub-topic categories or “campaigns,” are:
Neutron capture cross-section measurements Fission cross-section measurements The elasticity of cross-section measurements The inelasticity of cross-section measurements Fission neutron spectrum measurements Thermal scattering effects
Such measurements will include not only investigations into the reaction components involved in fast reactor thermo-nuclear systems, but also analyses of spent fuel.
To date, the Fast Reactor Research and Development sub-topic has begun to generate some data which will be of value in the other sub-topic categories. Instruments such as the Fission Time Projection Chamber (TPC) and the Lead Slowing Down Spectrometer (LSDS) have come into use. A new device, the Detector for Advanced Neutron Detector Experiments (DANCE), is being considered. The objective is to improve the precision of all the many diverse measurements of radio-activity encountered in nuclear fission reactions.
A multi-faceted team is proposed involving two of the DOE laboratories, the National Institute of Standards and Technology (NIST) and a consortium of eight universities capable of addressing some of these needs, which are involved through the DOE Nuclear Energy University Program (NEUP). To complement these measurement needs, an enhancement of the probability codes used in estimating or simulating these pertinent nuclear reactions is also needed.
1 – To facilitate understanding of the diverse requirements for supporting the fast reactor initiative, a coherent organization structure must be developed integrating all program aspects under a defined person in-charge who has total budgetary responsibility. Supporting institutions may have to assign personnel on a rotational basis in order to expedite completion of these needs. A fragmented approach is not only poor management, but also will delay achievement of desired results.
2 – Neutron cross section measurements and other radioactivity measurements should be implemented with state-of-the-art equipment.
3 – A permanent home for all nuclear measurement data should be established with sufficient continuing funding to enable the US to maintain leadership in this field.
4 – The development of a next generation of neutron detector systems is needed including such as those developed for the neutron induced fission fragment tracking time projection chamber, for the LSDS, for the DANCE, and others.
1 – A minimum of 2 NIST person-years per year over the next three year time period is required to launch NIST into these objectives.
2 – A steady funding source across DOE, DOD, NIST, NSF, or other sources, under a defined unified management structure, at about $30,000,000 per year is required to support these measurement efforts.
3 - Partnerships between NIST and DOE and other committed parties are essential in this area.