Application specific product qualification report for uninterruptible power supplies used in nuclear reactors R1 and R2
Authors: Sadeghi Sam 
Published: May 2021

Safety is the most important aspect and is considered the overwriting priority in nuclear power plants, which comprise of thousands of systems and components that work systematically together for the purpose of generating electricity in a safe, economical and environmentally friendly manner. As the instrumentation and electrical components advance and become more sophisticated and migrate from analog design to the more complicated and error-prone software-based topology, the task of determining that a programmable electronic system (PES) is capable of meeting its safety-related design objective becomes ever more challenging. The dependence on the PES to accomplish its safety-related object must be thoroughly studied to assess the safety-related impacts associated with the potential failure modes of the device. Application Specific Product Qualification (ASPQ) is used to provide neccessay aasurance in the design integrity of a PES and confirms that the product can meet the requirements of a safety-related application.

This report is an application specific product qualification (ASPQ) assessment of WEP 1010-110/120-NEA and WEP 1020-110/120-NEA Uninterruptible Power Supplies manufactured by Gambit Electronic Ltd. Information referenced in this report is based on the data received from Gambit, other nuclear power plants using Gambit products and the site visit paid to Gambit, Country-X in August 2007. Gambit WEP 1010- and 10XX-XXX/YY NEA UPS systems are used to provide uninterruptible Class II power to a number of safety-related control and instrumentation power distribution panels for R1 and R2 reactors located in X facility. These UPS are commercial Off-the Shelf (COTS) products intended for industrial uninterruptible power supply applications.

An earlier Categorization Assessment Report concluded that UPS perform Category B safety-related functions and therefore, they must be qualified to meet the safety requirements associated with a Class BProgrammable Electronic System (PES) as per IEC 61513.A combination of methods were utilized to demonstrate that the UPS systems were suitable for the target applications, were inherently correct in design, and came with sufficient documentation to allow safe operation by the plant. The key findings of this report indicate that the aforementioned UPS systems are suitable for use in the target application, have strong evidence of reliability through field experience and various product certifications that support correctness of their design and come with thorough documentation that support safe operation and suitability assessment. Two major recommendations made in this report are to establishing a Preventive Maintenance (PM) program by the station to perform replacement of life-limiting components at the minimum frequencies specified by the manufacturerer, and to set ip an inspection and testing program by the station to perform minimum -monthly testing of the output power quality of the UPS systems to minimize the possibility of partial failure, which is the failure of concern and relates to a situation where the loads are supplied with out-of-specification power, undetected.