The development of high-fidelity full-core modeling capabilities for LWRs is the stated goal of several projects such as CASL (Consortium for Advanced Simulation of LWRs). In this benchmark, the work performed by CASL in their VERA Core Physics Benchmark Progression Problems is extended into a Nuclear Energy Agency code-independent benchmark to encourage Verification and Validation (V&V) of traditional and novel high-fidelity Modelling and Simulation (M&S) from multiple participants.
The benchmark specifications originate from a selected set of CASL benchmark problems based on data provided by the Tennessee Valley Authority (TVA) and other references available in the public domain. It introduces a benchmark which provides detailed specifications of the WBN1 core operations measured by TVA. The data are provided for Watts Bar Unit 1 Cycle 1 (WBN1C1) and Cycle 2 (WBN1C2). Five exercises cover the key states of WBN1C1 and WBN1C2. The exercises span the start-up Zero Power Physics Tests (ZZPT), Hot Full Power (HFP) Beginning of Cycle (BOC) Physical Reactor, depletion of WBN1C1, fuel shuffle and decay for Cycle 2 BOC ZPPT, and WBN1C2 depletion.
In order to support the development of the VERA for multi-physics applications, CASL developed a set of benchmark progression problems ranging from simple two-dimensional pin cells to three-dimensional multi-physics reactor core problems. There are five exercises within the benchmark:
Exercise 1: Validation of stand–alone 3-D neutronics model at HZP conditions
This exercise aims to calculate the required parameters of the WBN1C1 ZPPT BOC startup. The loading pattern of this exercise is provided, the fuel assemblies in this exercise are at the beginning-of-life (BOL) conditions and the reactor is at Hot Zero Power (HZP) isothermal conditions. The initial criticality was achieved by inserting bank D while all other banks were fully withdrawn.
Exercise 2: Verification of multi-physics steady state model for HFP conditions
This exercise aims model WBN1C1 at nominal conditions with the loading pattern and material properties described in the benchmark. In this exercise, bank D is partially inserted while all the other RCCA banks are withdrawn. The prediction of the HFP distribution requires the calculation of the Xenon equilibrium across all the fuel rods in the reactor core. No measured data were provided by TVA for this exercise, therefore the reference results are taken from the calculated MC21/CTD simulation, published in report CASL-U-2015-1010-001.
Exercise 3: Validation of multi-physics cycle1 depletion model for Cycle 1
The exercise aims to predict the depletion of the WBN1C1 fuel, fission product build-up and decay and material activation within core structures. The averaged operating power history is provided in the benchmark specifications.
Exercise 4: Validation of fuel shuffle and decay for Cycle 2 BOC ZPPT
This exercise focuses on the analysis of the WBN1 refueling and the fuel reactivity at HZP conditions in Cycle 2. The loading pattern of this exercise is described in the specifications. The length of the refueling process between Cycle 1 and Cycle 2 is assumed to be 30 days and isotopic components, including those for boron, are provided.
Exercise 5: Validation of multi-physics cycle1 depletion model for Cycle 2
The exercise aims to predict the depletion of the WBN1C2 fuel, fission product build-up and decay and material activation within core structures. The loading pattern of this exercise is described in the specifications.
Details, including specifications and results templates can be found in the working area. To access the working area, please fill out the conditions form and e-mail it to wprs@oecd-nea.org.
TVA WB1 Benchmark (requires password | reminder)