Example of method 1 "Retrieving fuel debris from the top (fixed transporting equipment)”
Index
> Considerations - 1. Dose reduction|Example of method 1 "Retrieving fuel debris from the top (fixed transporting equipment)”
ⅱ) Considerations - 1. Dose reduction
Issues to be noted for the proposing method in terms of safety are explained below.
Clarification of objects for mote and close oprations
Method to minimize the workers' exposure
Issues requiring special attention 1. Dose reduction
(1) Prior preparation
Dose reduction for workers when transporting/installing equipment and removing it
Dose reduction for workers when investigating
(2) Install barrier
Dose reduction for workers when installing barrier
(3) Remove shield plug
Dose reduction for workers when removing shield plug
Dose rate reduction for external environment when removing shield plug
(4) Remove PCV/RPV upper head
Dose reduction for workers when removing PCV head/RPV head
Dose reduction for external environment when removing upper head
(5) Install equipment and access
(6) Dismantle and remove internal structures
Dose reduction for workers and external environment when dismantling and removing internal structures
(7) Retrieve fuel debris
Exposure of workers when cutting fuel debris
Dose reduction for external environment when cutting and storing fuel debris
(8) Collect fuel debris and transfer canisters
Dose reduction for workers when storing fuel debris
Dose reduction for external environment when storing fuel debris and transferring canisters
Dose reduction for external environment affected by the radiation from temporary storage area
(9) Clean-up equipment
Dose reduction for external environment when removing equipment
Plant information
Atmospheric environment inside PCV (temp, dose rate, etc.)
Plain view (Unit 1)
Plain view (Unit 2)
Plain view (Unit 3)
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
→ⅱ) Considerations - 2. Boundary