Session: 10-03: Advanced Manufacturing 3

Paper Number: 136504

136504 - Research on Qualification Requirements for Electrical and Instrumentation Equipment Based on Safety Classification 

Abstract: 

In 2014, the IAEA issued new safety classification guidelines for nuclear power plants called Safety Classification of Structures，Systems and Components in Nuclear Power Plants.It is stipulated that items are classified based on their function importance, and after determining the safety class, equipment qualification requirements need to be determined to ensure that items have suitable quality under all expected operating conditions and to ensure the realization of safety functions. Therefore, it is necessary to identify safety important items that can perform their necessary expected functions throughout their entire design operating life and under dominant environmental conditions, including maintenance and testing of nuclear power plants. The identification procedure for important safety items must take into account the aging effects caused by various environmental factors (such as vibration, radiation, humidity, temperature) during the expected lifespan of safety important items. Therefore, it is necessary to clarify the identification requirements for equipment and carry out equipment identification activities from the perspective of equipment selection. In order to establish the  qualification requirements for different safety class of electrical and instrumentation equipment under the IAEA SSG-30 classification principle, especially for the qualification requirements for equipment operated under design extension conditions.This article investigates the relevant codes and standards such as RCC-E and IEEE as well as different reactor experiences, and analyzes the actual environmental conditions under which electrical and instrumentation equipment performs its functions.This includes determining the environmental and load conditions for device execution, the timing and duration of device execution, and the type of function performed by the device. A method and related requirements for the classification of electrical and instrumentation equipment qualification levels are proposed, and their corresponding relationship with the functional class of IAEA SSG-30 devices is provided. The qualification requirements and classification method based on the IAEA SSG-30 classification principle studied in this article can be used to determine the qualification requirements for different functional class equipment, especially for electrical and instrumentation equipment classified as F-SC3 level.The F-SC1 and F-SC2 equipment are used for design basis accidents, using nuclear level qualification and applying the strictest qualification standards. The F-SC3 equipment is designed for use in extended operating conditions, disaster prevention, and off-site emergency situations, and its equipment qualification requirements are not clear. This article divides equipment qualification into different qualification levels based on the location inside or outside the containment, the environmental conditions including temperature, pressure, and radiation conditions, the operating conditions for executing functions such as design basis accident design extension conditions, and specifies the tests required for equipment of different qualification levels.

Presenting Author: Qian Sun CNPE

Presenting Author Biography: A senior engineer working in CNPE, who major in I&C safety classification and qualification and nuclear power plant operation.

Authors:

Qian Sun CNPE
Jiahao Liu CNPE