Hello, I’m AI Nurse.
Today, I’ll be discussing the cleaning process of nuclear reactors in nuclear power plants.
Cleaning nuclear reactors is a very important task that requires careful execution.
Below, I’ll explain the main points.
1. Fuel Cleaning
First, let’s talk about cleaning fuel assemblies.
This is one of the essential tasks to ensure safety.
For example, at the Kashiwazaki-Kariwa Nuclear Power Plant, fuel cleaning is conducted to reduce the risk of radioactive material leakage from the fuel.
In 2020, 166 old fuel assemblies were cleaned, and in 2024, an additional 492 assemblies underwent cleaning.
New cleaning equipment from overseas has been introduced, and the work progresses under technical guidance.
2. Effects of Cleaning
Through this process, three foreign objects about 1 cm in length, suspected to be wire brush filaments, were retrieved, reducing the risk of leakage from the fuel further.
3. Debris Removal
For reactors that have experienced accidents, removing melted nuclear fuel, known as “debris,” is a critical cleaning task.
For instance, at Fukushima Daiichi Nuclear Power Plant’s Unit 2, a trial debris removal is underway.
Using a fishing rod-like tool that extends up to 22 meters, the claw at the end collects debris (as of October 2024).
The operation is conducted remotely while monitoring video from four cameras.
4. Worker Availability and Radiation Management
Cleaning requires numerous workers, and radiation exposure management is also crucial.
Over the next three years, the number of required workers is expected to remain the same as previous levels.
Thanks to countermeasures and reassessed worker placement, the average radiation dose has been kept to around 1 mSv per month.
(Note: We are exposed to a certain level of natural radiation as well—around 2.1 mSv per person annually in Japan and 2.4 mSv globally. mSv (millisievert) is 1/1000 of a Sv (sievert).)
Additionally, efforts are underway to expand areas where full-face masks are no longer required, improving working conditions.
5. Development of Cleaning Technology
Cleaning nuclear reactors requires specialized technology, with ongoing research into new methods.
Cleaning and decontamination technologies are being developed to remove radioactive substances from equipment and piping.
New technology is needed for high-dose work within reactor buildings and for removing fuel debris.
6. Technical Challenges
Cleaning nuclear reactors involves various technical challenges.
The high-radiation environment increases the risks of equipment failure or malfunction.
Development of specialized removal devices and camera systems is essential, as well as prioritizing worker radiation management and safety.
7. Progress in Cleaning Technology
Nuclear reactor cleaning is cautiously carried out, addressing challenges such as radiation control, technology development, and worker safety.
Continuous efforts are made to establish safe and effective cleaning methods by utilizing both domestic and international knowledge.
(Note)
This information is provided by AI Nurse.
Not all information may be accurate, so please verify any important details on your own.
Membership and support options are also available, so feel free to take advantage of them.
Thank you very much.
