Main challenges & solutions

The full scope simulators of Member States have high usage to ensure each NPP has enough authorized/licensed operators for continued operation. With an aging nuclear industry workforce high availability and reliability of simulators is paramount to meet the required training of replacement authorized MCR personnel and to facilitate the continued training and re-authorisation of existing staff. To accomplish this objective several strategies are recommended:

 Review and upgrade the simulator hardware and software periodically;

 Upgrade the simulation environment with graphical tools to make it easier to maintain and update parameters such as deficiency clearance or incorporate plant modifications;

 Maximize the use of commercial off-the-shelf hardware (e.g. computers, network equipment, power supplies, etc.) and third-party software (e.g. operating systems, compilers, databases, etc.);

 Pro-actively address obsolescence issues (e.g. spare parts management, re-engineering of instruments, etc.);

 Add of UPS and power conditioner and redundant power sources to prevent equipment failures due to power outages and surges;

 Have physical server clones for hot standby or virtualized services which can be quickly switched into action when problems occur;

 Utilize the multi-CPU performance of modern hardware and minimize the number of separate computer systems for critical infrastructure instead of using clusters of computers which fail when a single unit fails;

 Review and rehearse the back-up and recovery procedure periodically, implement automated back-up of all relevant data;

 Delegate development and testing efforts to secondary simulators and minimize the need for the FSS for project works and upgrades.

These strategies will result in less equipment failures and overall easier maintenance of the simulator.

2.6.2. Configuration management/control

Whether for an NNB or existing NPP simulator, keeping the simulator up to date with the plant design (configuration management) is a challenge. NPPs need to establish a strong engineering process such that all plant modifications are evaluated for simulator impact. If a specific plant modification is flagged to impact the simulator, the simulator staff needs to scope the hardware and software changes required. The implementation of plant modifications needs to be prioritized based on training needs. Plant changes impacting plant operation significantly may even be implemented in the simulator before implementation on the plant. This approach is considered industry best practice.

Another aspect is configuration control of the software models and source code to ensure integrity of the simulator software configuration and proper documentation supporting simulator changes. Some simulation environments include built-in advanced configuration control (versioning) and configuration management tools to facilitate this. These tools include graphical and non-graphical comparison and data tracking features such that plant data, stored into a repository, can be linked with the model. Some third-party configuration management software can also be utilized but they are typically not ideal for graphical models and do not allow for creating links between the software and the plant design data. Utilize modern web based ‘ticket’ or work management systems for handling the simulator change management workflow and tie this system in with the configuration and version control system. Make both available directly on the simulator computer network so they become a part of daily life for all personnel involved.

2.6.3. Nuclear new builds simulator development

Experience has shown that developing an operator training simulator in time to train and examine plant operators before fuel loading is a major undertaking. NNB plants are highly DCS based and the DCS design changes constantly until very late in the plant construction phase.

Therefore, simulator vendors need to find innovative ways to cope with this and ensure the simulator will be ready for operator training. Here are some recommended strategies:

 Engineering simulators can and should be used to assist in plant/DCS engineering (experience has shown that this practice allows for the early identification and resolution of a significant amount of plant design issues) graphical models and real-time graphics allow for prototyping, quick changes and immediate feedback. Modification and fidelity accuracy are paramount as this simulator will eventually become the operator training simulator;

 Seamless organizational integration of simulators with the DCS design and implementation is key;

 Simulation models should match one-to-one plant design documents/drawings to facilitate incorporation of plant changes;

 Using DCS simulation upfront should be considered, such that the simulator is not dependent on the plant DCS design and configuration; emulation or stimulation can be introduced later once the DCS design is more stable. Alternatively, the DCS design could be led on an engineering simulator with implementation to the real unit once the simulator

works as designed, providing that the DCS system chosen supports a flexible stimulation/emulation capability with quick change implementation and initial condition handling;

 Automation of the process to update the simulator DCS controls and HMI (DCS translation process) is key to a quick update of the simulator;

 Strong configuration management and control tools designed for graphical models and graphics is essential.

2.6.4. Existing NPPs external systems incorporation

Another challenge for existing NPPs is the addition of external systems (DCS, digital instruments, Plant Process Computers (PPCs, etc.). Original Equipment Manufacturers (OEM) are typically not forthcoming with technical information on their hardware and software (for Intellectual Property (IP) considerations) making their implementation in simulators challenging. Some of the external systems do not support inherent simulator functions, such as freeze/run, restore/store Initial Condition (IC), etc. The following four strategies are possible for their implementation:

 Stimulation;

 Emulation;

 Simulation;

 Hybrid approach (mix of different strategies for controls and HMI).

Here are some strategy selection factors to consider when implementing external systems:

 Project strategy and schedule;

 Data availability (plant vs. simulator timing);

 Vendor selection (OEM IP considerations);

 Cost of hardware, development and software licenses (including consideration for classroom simulators);

 Licensing restrictions;

 Classroom simulators (portability of hardware/software);

 Configuration control/management (level of effort to implement future plant changes);

 Fidelity requirements;

 Preferences.

2.6.5. Meeting operator expectations

As NPPs become more digitalized, the simulators’ response can be evaluated with more detailed scrutiny than ever before. Simulators can be benchmarked against actual plant events to ensure that the simulators properly replicate the NPP response to the specific operation or event. Operators can now easily obtain trends of any plant parameter to analyse (and no longer need to rely solely on instantaneous readings from instruments) to benchmark simulator fidelity.

Operators now expect increasingly realistic scenarios from their site-specific simulators when training. Therefore, it is important to improve simulator fidelity and capabilities over time by incorporating new technologies and learning to ensure the operators continue to ‘trust and respect’ their simulators. Regular polls and questionnaires can be used to record client (operator and instructor) sentiment on the quality and performance of the simulator, as well as find key areas for improvement and topics for which future life cycle development effort should be directed by the technical crew maintaining and developing the simulators.

3. ANALYSIS, DESIGN AND DEVELOPMENT OF TRAINING PROGRAMMES FOR SIMULATOR TRAINING