Example of method 3 "Retrieving fuel debris from the side”

Index > Challenges and Plant information : Overview of methods ｜Example of method 3 "Retrieving fuel debris from the side” > (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)Create opening on the side of PCV

(4) Install equipment and access

(5)Dismantle and remove internal structures

(6)Retrieve fuel debris

(7)Transport canister

(8)Clean-up equipment

Check before operation.

How to confirm the following

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	Atmospheric environment inside PCV (temp, dose rate, etc.) Plain view (Unit 1) Plain view (Unit 2) Plain view (Unit 3) Schematic diagram for internal structures Location and amount of fuel debris Dimension and weight of internal structures Injection of nitrogen gas and gas control system

Assumptions and prerequisites	Air dose rate inside the PCV/RPV - Dose rate inside the PCV 100Gy/h - Dose rate inside the RPV 1kGy/h PCV exterior effective dose rate - Operation floor : 1mSv/h - Operation areas other than 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