May-June 2019 NPJ

(Continued on page 26) I&C Commissioning of AP1000 Reactors in China By H.M. Hashemian and Ryan O’Hagan, Analysis and Measurement Services Corporation. H.M. Hashemian H.M. “Hash” Hashemian is President and Chief Executive Officer of Analysis and Measurement Services Corporation (AMS), a 42-year old nuclear engineering consulting firm headquartered in Knoxville, Tennessee, and operating in the United States, Europe, and Asia. He has three doctorate degrees in engineering, including a Ph.D. in nuclear engineering, a Doctor of Engineering degree in electrical engineering, and a Ph.D. in computer engineering. Dr. Hashemian is the author of three books: Sensor Performance and Reliability (ISA, 2005), Maintenance of Process Instrumentation in Nuclear Power Plants (Springer Verlag, 2006), and Monitoring and Measuring I&C Performance in Nuclear Power Plants (ISA, 2014). His books have been translated into Chinese, Japanese, Korean, and Russian. In addition, he is the author or co-author of 20 U.S. patents (17 awarded and 3 pending). Dr. Hashemian is a Fellow of the American Nuclear Society, a Fellow of the Institute of Electrical and Electronics Engineers, a Fellow of the International Society of Automation, and an adjunct professor of nuclear engineering at the University of Tennessee. 1. Introduction The first four AP1000 reactors in the world came online in China in 2018 and 2019. Two of the AP1000 units are located at the Sanmen site in the province of Zhejiang, and the other two at the Haiyang site in the province of Shandong. Both sites are within 500 miles of Shanghai. The Sanmen site belongs to Sanmen Nuclear Power Company, and the Haiyang site belongs to Shandong Nuclear Power Company. TheAP1000 plants areWestinghouse Pressurized Water Reactors (PWRs) with passive safety features and modern Instrumentation and Control (I&C) systems;making themeven safer andmore efficient than the existing generation of Westinghouse PWRs. As with most PWRs round the world, t is mandatory for AP1000 reactors to measure the response imes of their safety elated sensors at east once every operating cycle. To comply with hese requirements, he Sanmen and Haiyang plants ontracted AMS to perform response ime measurements on their temperature sensors and pressure, level, and flow transmitters that are used to control the plants and monitor their safety. AMS also verified the electrical integrity of the sensor and transmitter cables and collected baseline cable data to help with any future cable troubleshooting, condition monitoring, or aging management. Through this work, a few sensor response time and cable issues were identified and resolved leading to successful dynamic performance of the sensors and integrity of their cables. The sensor response time testing and cable measurement technologies used by AMS in China has been in public domain for decades and used in thousands of tests in nuclear plants around the world. As such, AMS verified through written communication with the U.S. Department of Energy’s National Nuclear Security Administration that the work that AMS has performed in China is not subject to export control requirements of the U.S. government. 2. Background To ensure the safe and efficient operation of a PWR, the response time and calibration of I&C sensors that provide input to the plant protection system must be verified periodically as specified in industry standards, guidelines, and regulations. These include Regulatory Guide 1.118 and NUREG-0800 of the U.S. Nuclear Regulatory Commission (NRC), Standard 67.06 of the International Society of Automation (ISA), Standards 62385, 62397, and 62342 of the International Electrotechnical Commission (IEC), and TECDOC 1147 and 1402 of the International Atomic Energy Agency (IAEA). The Institute of Electrical and Electronics Engineers (IEEE) and Electric Power Research Institute (EPRI) have also published documents that relate to response time testing of nuclear plant I&C sensors. In particular, EPRI pioneered the development of sensor response time testing techniques such as the Loop Current Step Response (LCSR) test for Resistance Temperature Detectors (RTDs) and the Ramp Test technique for pressure, level, and flow transmitters. These techniques were developed in the late 1970s and have since been used in thousands of tests in PWR plants around the world. In fact, before a new PWR plant can start commercial operation, the response times of its safety-relatedprocess sensors must be measured and compared with the plant technical specification requirements. Sensor response time as measured in a laboratory or by the original equipment manufacturer prior to installation in the plant is not adequate for commissioning of nuclear plants for the following reasons: 1) The response time of an RTD depends on the quality of its fit to its thermowell and the plant operating conditions including the process temperature, pressure, and flow. Even when an RTD is matched with a thermowell, its response time must be measured after installation in the plant because the RTD response time can a i t r l t t c t NuclearPlantJournal.com 25 Nuclear Plant Journal, May-June 2019