Inter-Ministerial Council for Contaminated Water and Decommissioning Issues (2019) Mid-and-Long-Term Roadmap towards the Decommissioning of Fukushima Daiichi Nuclear Power Station.

has been cited by the following article:

• TITLE: Development of Measurement System for Flow and Shape Using Array Ultrasonic Sensors

  AUTHORS: Munkhbat Batsaikhan, Zeliang Zhang, Hideharu Takahashi, Hiroshige Kikura

  KEYWORDS: Reactor Decommissioning, Sectorial Array Sensors, Total Focusing Method (TFM), Ultrasound, Ultrasonic Velocity Profiler (UVP), Vector Flow Mapping

  JOURNAL NAME: Journal of Flow Control, Measurement & Visualization, Vol.9 No.3, July 27, 2021

  ABSTRACT: In Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, the fuel debris formed in the Reactor Pressure Vessel (RPV) and Primary Containment Vessel (PCV) at Unit 1-3. To accelerate and decide further decommissioning steps of the FDNPP, it is crucial to obtain realistic information of the debris and localize contaminated water leakage from PCV. Due to high radiationand dark environment inside the PCV, investigating instruments andtechniques should necessarily to meet specification of radiation resistance,waterproofness, dust resistance and so on. This study focuses on development of ultrasonic measurement system using a couple of sectorial array sensors tolocalize contaminated water leakage and visualize shape of object thatrepre-senting fuel debris, simultaneously. In this study, Total Focusing Method(TFM) and Ultrasonic Velocity Profiler (UVP) methods are considered to visualize object shape and flow pattern around it, respectively. To demonstrate applicability and reliability of developed measurement system with sectorial array sensors, a mock-up experiment resultof simulated water leakage and fuel debris shape were discussed in this paper.