Plant aging Steam Generator Corrosion

[koab1mjr]

Hi

I am told that steam generator is an area that is suseptible to aging effects and corrosion. I was wondering if anyone can elaborate on this a bit. Is it just due to the heat and humididty? I am studying BWRs and safety and maintanced aspects and I was thinking of focusing on this area of plant.

Thanks

 

[gmax137]

I am told that steam generator is an area that is suseptible to aging effects and corrosion. I was wondering if anyone can elaborate on this a bit. Is it just due to the heat and humididty?

No, the chemistry of the feedwater is critically important, as is the material of the SG tubes (e.g., Inconel 600 vs. 690). The fabrication method (how the tubes are held in the tubesheet) may also play a role (through the stress in the joint). Google 'stress corrosion cracking'. Look on the NRC site under 'Alloy 600'.

I am studying BWRs and safety and maintanced aspects and I was thinking of focusing on this area of plant.

This doesn't make sense: BWRs do not have steam generators.

 

[koab1mjr]

Thanks for the response. Sorry I misspoke the steam line. Forgot BWR make steam right in the vessel. Is it true that both require separation of water vs steam. Is that where the steam line comes in.

Lastly why would a rupture in the steam line cause pressure in the reactor to decrease i would figure the opposite would occur.

Anyway I am very new to this stuff so sorry if these questions seem obvious or whatever.

I will look up stress corrosion though

 

[Astronuc]

Main Steam line break would cause loss of pressure because the system looses inventory.

The primary cooling system is more or less closed (excluding make up and leakage).

BWRs have steam separators and dryers that allow 'dry' steam (as dry at saturated conditions as possible without superheat) to pass to the high pressure turbine. The separators and dryers are stainless steel, which are subject to stress corrosion cracking.

Corrosion is a function of material composition (chemistry), microstructure (which is affected by fabrication processes), and environment (time, temperature, stress and water chemistry, and radation to some extent). There are nickel-bearing materials (Inconels) in some BWR components.

Stainless steels and Inconels are susceptible to Intergranular (IG) stress corrosion cracking (SCC), or Irradiation-Assisted (IA) SCC.

 

[alphy]

for your question! I can provide some insight into the factors that contribute to plant aging and steam generator corrosion. The steam generator is a critical component in a nuclear power plant, responsible for converting water into steam that drives the turbines to generate electricity.

One of the main reasons for steam generator aging is the constant exposure to high temperatures and pressures, which can cause wear and tear on the equipment over time. This is exacerbated by the presence of moisture and oxygen, which can lead to corrosion of the metal components. The high temperatures also promote chemical reactions that can cause deposits and buildup on the tubes and other surfaces within the steam generator, reducing its efficiency and potentially leading to failures.

In addition to these physical and chemical factors, human error and maintenance issues can also contribute to steam generator aging and corrosion. It is important for nuclear power plants to have strict protocols and regular maintenance schedules in place to monitor and address any potential issues before they become major problems.

As you mentioned, BWRs (boiling water reactors) are particularly susceptible to steam generator corrosion due to the high temperatures and humidity within the reactor. It is essential for operators to closely monitor and maintain the steam generator in these types of reactors to ensure safe and efficient operation.

In terms of safety and maintenance, it is crucial for nuclear power plants to have robust inspection and maintenance programs in place to detect and address any aging or corrosion issues in the steam generator. This can include regular inspections, cleaning, and replacement of worn components to ensure the long-term reliability of the equipment.

I hope this information has been helpful in understanding the factors that contribute to plant aging and steam generator corrosion. It is an important area of study and maintenance in the nuclear power industry to ensure safe and efficient operation of these facilities.