Assessing Nuclear Safety Related Control and Instrumentation Systems
Learn how our Safety, Risk and Compliance team assessed an international power generation company's nuclear safety related control and instrumentation systems (C&I) in accordance with modern standards and in support of an aging and obsolescence management program. The assessment formed a key component in demonstrating that the control systems were operating efficiently and reliably and should continue to do so, thus decreasing the immediate need for replacement.
ABS Group previously helped develop an aging and obsolescence strategy for nuclear safety related C&I systems at an international power generation company. Our Safety, Risk and Compliance team was retained again to conduct independent assessments of the same systems as compared to and in accordance with modern standards. The systems were aging and had an increasing number of obsolete components. Our safety, risk and compliance management assessments provided the company with a baseline to work from for the aging and obsolescence strategy.
As part of this solution, ABS Group adapted a client supplied methodology to perform the in-depth modern standards review of complex, nuclear safety related control systems. Our engineers examined the system design and operations and maintenance procedures to provide the client with a baseline judgement of its control systems compliance. Potential shortfalls against modern standards were identified and solutions proposed to address and/or mitigate the risks, which enabled the company to be in a better position to evaluate its options as part of the aging and obsolescence strategy.
- Review and compare systems for compliance with modern design, operations and maintenance standards
- Develop solutions to address any identified shortfalls
- Determine whether the existing safety-related C&I systems can be retained, need to be replaced or require additional support systems
Compile technical information about the C&I systems by examining design, maintenance and operations documents, and enhance understanding through discussions with operators and maintainers
Use the knowledge/understanding gathered to perform the modern standards review; follow with a review meeting to confirm that the information is correct
Work with operators and maintainers to develop solutions addressing any identified shortfalls
Present the review/recommendations in a final report providing the overall judgment of compliance with modern standards
Include an outline as to any changes to the overall judgment that can be achieved by completing the recommendations successfully
For each location, ABS Group engineers examined a wide range of design, commissioning and testing documentation to gain an understanding of the data processing and control systems which provide information to operators, raise alarms and perform automatic reactor control. Using the information gathered and following discussions with site system engineers, we performed a design review for the systems at each location to confirm whether or not the C&I systems were in compliance with modern standards. Topic areas included system architecture, technology, development processes and design substantiation.
Our engineers worked closely with the client to clarify technical points and to verify that the review information was accurate. The design reviews identified several potential shortfalls for which mitigation and additional recommendations were presented, including design documentation not providing sufficient substantiation of reliability to satisfy modern standards and a risk that self-diagnostics might be inadequate. For the first potential shortfall, we recommended a review to reduce reliability claims, if possible, combined with additional documentation and analysis to fully support the remaining claims. For the second potential shortfall, we recommended a review of diagnostic capability to determine if the systems were consistent with modern standards requirements. The consensus was that these systems might not be compliant with modern standards and that the shortfalls should be addressed. Following successful completion of the recommendations, we reassessed the systems and determined that the design was now compliant with modern standards.
Operations and Maintenance Review
ABS Group engineers started by examining operational manuals and maintenance documents as well as records to understand how the C&I systems had been operated and maintained. This information was used to conduct an operations and maintenance review that covered the topics of maintenance, testing, aging and obsolescence, equipment condition, resources and configuration control among others. Meetings with system engineers were held to review the information compiled in order to verify that the information was technically sound and that all of the significant operations and maintenance aspects had been captured in accordance with these standards.
The systems were considered to be acceptable based on the operation and maintenance requirements, although improved compliance to 100% was recommended as a best case to promote safer, more reliable systems operations through the complete life cycle.
By verifying the control system design and operations and maintenance standards, an international power generation company gained an increased confidence that its C&I systems would continue to operate efficiently and reliably provided that a number of recommendations were completed.
The recommendations provided by ABS Group supported the continued use of the client's existing systems and reduced the need for complete system replacement, which would have come at significant cost and might also have been challenging from a safety perspective. The risk assessment also provided a platform for further development of the aging and obsolescence management strategy to keep nuclear power a viable component of the client's energy supply strategy.