The JEFF-3.1.1 Nuclear Data Library; NEA Data Bank (May 2009).
This report describes the incremental method used to improve JEFF evaluations since the release of the JEF-2.2 library in 1992. In order to be accepted as a JEFF-3 evaluation, new evaluations must be demonstrated to be more consistent with both differential and targeted integral measurements. The report first describes the validation of the JEF-2 library and the user feedback received by evaluators. The main improvements introduced in the JEFF-3.0 file, and in a second step in JEFF-3.1, are then presented. The report highlights the modifications that would be required for JEFF-3.1 evaluations to fit with integral experiments and to meet LWR target accuracy. The new evaluations (237Np, 239Pu, 16O, 91,96Zr and seven fission products) introduced in the recommended JEFF-3.1.1 file are also described.
The current validation of the JEFF-3.1.1 file is detailed. Fundamental targeted experiments, LWR mock-up experiments, PWR and BWR chemical assays and SNF reactivity worth measurements are analysed using both TRIPOLI4 and APOLLO2.8 reference calculations.
This report demonstrates that JEFF-3.1.1 is probably the best international library currently available. It is more accurate than ENDFB/VII for fuel inventory, MOX reactivity and plutonium ageing, and reactivity coefficients such as temperature coefficient and stainless tell reflectors. Moreover, JEFF-3.1.1 evaluations benefit from the feedback of validation studies for fast breeder reactors, the fuel cycle, criticality safety and burn-up credit. JEFF-3.1.1 is used worldwide for PWR and BWR calculations, particularly in the new ARCADIA package of Areva-NP. It is also used in ERANOS2 for Generation IV designs.