Nuclear Simulation Laboratory

GPWR simulator

The recently renovated Nuclear Simulation Laboratory (NSL) is equipped with GSE‘s Generic Pressurizer Water Reactor (GPWR) simulator to support nuclear power related research activities and educational curriculum in the Department of Engineering.

The GPWR model is based upon a reference US nuclear plant that has been in operation and training for over 20 years. The GPWR reference simulator has been built and tested to the American Nuclear Society ANSI/ANS 3.5 Nuclear Simulator Standard. The reference plant simulator and training programs have been rigorously audited by the US NRC and INPO to ensure compliance with regulations and industry standards. The GPWR includes high fidelity models that allow full plant operation including Normal Operations, Abnormal Operations and Emergency Operations as required by ANS-3.5 and the simulator response has been validated against actual operating plant data.

As a full nuclear simulator, it allows for the entire range of operations experienced in a commercial nuclear power plant. The simulator has been integrated into NE 201 and NE 403 to assist students in understanding reactor systems and processes needed for normal and emergency operations.

NSL is equipped with a VPanel glass-top control panel, which is a touch screen embedded in the JClassRoom environment. It enables control operations to be made and simulation results to be received in real-time from the simulation. It is a great addition for human factor engineering (HFE) research.

In addition to the graphical interface as part of the GPWR simulator, the NSL lab also has a IFE’s UNID interface displayed in three large monitors. The UNID system developed by IFE enables students to monitor the state of the plant through several innovative displays designed to provide information on plant systems. The plant parameters are displayed using unique visual indicators that allow students to quickly identify changing conditions in the plant. These are software displays that are state-of-the-art, that is, they reflect where the industry is heading in upgrading the control rooms based on the latest HFE principles.

High-fidelity HTGR Simulator

A newer simulator has been co-developed and installed in the NSL to represent advanced reactor concepts. The model is based on the Xe-100 high-temperature gas-cooled reactor (HTGR) design. It is an advanced modular, 200 MWth, graphite moderated, helium cooled, pebble bed, high temperature reactor being designed by X-energy. The Xe-100 is fueled with 220,000 billiard ball sized graphite pebbles that contain thousands of specially coated Tristructural Isotropic (TRISO) uranium fuel particles enriched to 15.5%.

To model the Xe-100, a plant simulator has been developed using SimuPACT to accurately simulate transients and the corresponding system response. SimuPACT is an object oriented software environment developed by SimGenics that allows one to develop control system scripts, create and load snapshots of system initial conditions, fully control simulator execution, initiate generic and specific equipment malfunctions, create displays to view process variable trends, and create scenarios to simulate specific operation or transients.

SimuPACT utilizes Flownex as its flow solver to accurately simulate transients and the corresponding system response. Flownex is a NQA1 quality assurance flow solver with nuclear accreditation that utilizes point kinetic equations coupled with thermal hydraulic models to capture reactivity feedback during a transient. Flownex has both iterative and non-iterative solvers for increased calculation accuracy, numerical stability, and allows for real-time simulation. The SimuPACT Xe-100 plant model is organized into different subsystems that include the primary flow loop system, secondary flow loop system, control system, reactor core system, startup & shutdown system, and electrical network. This model is capable of simulating start-up control from cold shutdown to 100% nominal power, shutdown control from 100% nominal power to cold shutdown, steady state operation in cold shutdown conditions, steady state operation in hot shutdown conditions, steady state operation in low power conditions, steady state operation in high power conditions, load following between 25% and 100%, and various transients. To control the system during these scenarios, a control system built with cascaded Proportional-Integral-Derivative (PID) controllers is implemented to allow transition between different plant states.

A human-machine-interface (HMI) also been developed by NC State to facilitate the full control of the HTGR system from a graphical interface.