What is the problem that arises
from the steam generator accumulated sludge?

The accumulation of sludge intensifies due to the growth in operating rings in the steam generator of the power nuclear power plant. Harmful impurities that accumulate in sludge cause various problems during operation of the steam generator.
Not only reduces the heat transfer capacity of the steam generator but also interferes with the flow of the fluid between the tube and the support plate structure, resulting in thermal hydrodynamic instability and stress corrosion cracking in the tube plate and tube support plate tube, making it difficult to operate the steam generator.

Recent degradation and performance decline of steam generator tubes due to sludge has become an important issue related to the management of steam generator soundness. GEUMHWA WTS is actively participating to solve this problem.

What is the way to remove accumulated sludge?

The 'sludge lancing operation', which washes the sludge by spraying back pressure water for a long time as a means of removing accumulated sludge, is mainly used. However, this method has a disadvantage that it can only remove some sludge in the upper part of the plate. In recent years, chemical cleaning methods have been applied globally as an effective means to completely remove deposited sludge if there is danger or worries of danger to soundness of steam generators due to sludge.

GEUMHWA WTS introduced 'EPRI / SGOG Chemical Cleaning Technology' in 2007 and since then has applied chemical cleaning processes to domestic nuclear power plants 10 times.

Chemical cleaning?

In general, chemical cleaning can be divided into partial chemical cleaning and electro-chemical cleaning depending on the application range. Depending on the type and distribution of the accumulated sludge, a high-temperature and high-concentration chemical cleaning method and a low-concentration ASCA cleaning method are applied.

Chemical cleaning technology is very useful technology to maintain the steam generator soundness and is widely used around the world, and GEUMHWA WTS is working with DEI of USA to develop the technology.

What is the application format of chemical cleaning methods?

Because the types of steam generators are different for each nuclear power plant,
the type and area of sludge accumulation is different and the type of tube deterioration due to sludge is different.
Therefore, various cleaning methods can be selectively applied through thorough preliminary examination and analysis.

It is important to apply chemical cleaning as a preventive measure rather than as a counter measure.
GEUMHWA WTS is ready to apply this technology.