For coal fired power plant, clinker (coal ash) sticks to boiler tubes and to un-even part during operation and sometimes it growth up to several tons. To start work inside boiler furnace, it is necessary to remove such clinkers first but in many cases it is very dangerous.
The answer is Taihei Clinker Removal Method. By this method, clinker removal work can be done from outside of the boiler immediately after the outage with high temperature and dusty conditions.