Example of method 2 "Retrieving fuel debris from the top (mobile platform)”

Index > Challenges and Plant information : Overview of methods｜Example of method 2 "Retrieving fuel debris from the top (mobile platform)” >  (1) Prior preparation

ⅰ) Challenges and reference information : (1) Prior preparation

Task(s): Visual and measurement technology development for check work when retrieving fuel debris.

(1) Prior preparation - Major challenges on the actual method

(1)Prior preparation (2)Install barrier (3)Remove shield plug (4)Remove PCV/RPV upper head (5)Install equipment and access (6)Dismantle and remove internal structures (7)Retrieve fuel debris (8)Collect fuel debris and Transfer canister (9)Clean-up equipment

Check before operation

How to confirm the following

  • Condition of existing shield plug
  • Condition of PCV/RPV upper head
  • Location, shape and condition of internal structures
  • Location, shape and condition of fuel debris
  • Condition of hydrogen accumulation
  • Condition of radiation dose rate
  • Condition of dust
⇒Visual and measurement technology
Plant information
Assumptions and prerequisites
  • Air dose rate inside the PCV/RPV
    - Dose rate inside the PCV 100Gy/h
    - Dose rate inside the RPV 1kGy/h
  • Effective dose rate outside the PCV
    - Operation floor : 1mSv/h
    - Operation areas except for operation floor : 3mSv/h
    - Passageway inside the building : 5mSv/h
  • Give consideration to the possibility of the accumulation of hydrogen gas inside PCV/RPV when cutting fuel debris or internal structures.
→(2) Install barrier