In recent years there has been an increasing demand from nuclear research, industry, safety and regulation for best
estimate predictions to be provided with their confidence bounds. Consequently, the OECD/NEA has set up an Expert Group
on Uncertainty Analysis in Modelling (UAM).
One of the objectives is to draw a roadmap for the development and validation of the methods and codes required for
uncertainty analysis including the benchmarks adequate to determine the uncertainty in LWR systems and processes in all
stages of calculations. Reference systems and scenarios for coupled code analysis are defined for this purpose.
Measured data from plant operation for the chosen scenarios will be used Use will be made of date made available within
the BWR Turbine Trip (TT), PWR Main Steam Line Break (MSLB), VVER-1000 Coolant Transients (V1000CT) and BWR Full Bundle
Test (BFBT) benchmark studies.
In order to achieve this the following procedure is used:
a) to subdivide the complex system/scenario into several steps (Exercises),
b) to identify input, output and assumptions for each step,
c) to calculate the uncertainty in each step;
d) to propagate the uncertainty for the evaluation of the overall system/scenario.
Nine steps (Exercises) will allow to develop a benchmark framework which mixes information from the available integral
facility and NPP experimental dat with analytical and numerical benchmarking. These 9 steps (Exercises) will be carried out in 3 phases each covering a two-year period.
The work of the group addresses mainly the scientific aspects of the methodologies being developed and demonstrate
their validity. This work will interface with the activities of the CSNI who would later address any licensing issues.
In this 'package' the information from the different exercises and workshops is gathered. It contains:
- Presentations made at UAM-2006 (28-29/04/2006, Pisa)
- Proceedings of the First Workshop - UAM-1 (10-11/05/2007, Issy-les-Mx)
- Proceedings of the Second Workshop - UAM-2 (02-04/04/2008, Garching)
- Proceedings of the Third Workshop - UAM-3 (29/04 - 1/05 2009, PSU)
- Proceedings of the Fourth Workshop - UAM-4 (14-16/04/2011, Pisa)
- Proceedings of the Fifth Workshop - UAM-5 (13-15/04/2011, Stockholm)
Restricted to participants in these benchmarks.