Benchmark for Uncertainty Analysis in Modelling (UAM) for Design, Operation and Safety Analysis of LWRs - Volume II: Specification and Support Data for the Core Cases (Phase II)

The objective of the OECD LWR UAM activity is to establish an internationally accepted benchmark framework to compare, assess and further develop different uncertainty analysis methods associated with the design, operation and safety of LWRs. As a result, the LWR UAM benchmark will help to address current nuclear power generation industry and regulation needs and issues related to practical implementation of risk informed regulation.

This specification document covers Phase II, which includes the second three Exercises (core) as follows:

• Chapter 2 of this document provides the definition of Exercise II-1.
• Chapter 3 provides the definition of Exercise II-2.
• Chapter 4 provides the definition of Exercise II-3.
• Chapter 5 specifies the requested output for the three exercises.
• Chapter 6 provides summary and conclusions.

This phase is focused on understanding uncertainties in prediction of key reactor core parameters associated with LWR stand-alone fuel performance, thermal-hydraulics and neutron kinetics core simulation. Such uncertainties occur due to input data uncertainties, modelling errors, and numerical approximations. Phase II addresses time-dependent neutronics (kinetics and depletion), thermal-hydraulics, and fuel performance without any coupling between the three physics phenomena. Output parameters and propagated parameters are defined for exercises of Phases II for the three main types of LWRs selected in UAM (PWR, BWR and VVER). These three main LWR types are selected, based on previous benchmark experience and available data:

• PWR (TMI-1)
• BWR (Peach Bottom-2)
• VVER-1000 (Kozloduy-6, Kalinin-3)