Flow Accelerated Corrosion (FAC)

Question 1

What industry event led to the development of the FLow Accelerated Corrosion program?

Answer 1

Surry-2, in 1986

4 people died, more injured

Question 2

Describe flow accelerated corrosion (FAC)?

Answer 2

• Protective oxide layer dissolves into flowing stream
• results in global attack (wide spread thinning)
• failures are sudden and catastrophic

Question 3

What are the major factors that affect flow accelerated corrosion (FAC)?

(6)

Answer 3

1. Fluid velocity (faster = worse)
2. Steam quality (more moisture = worse)
3. component geometry (turbulence = worse)
4. Chemistry (lower pH = worse, deoxygenated water susceptible)
5. piping material (chromium 0.1 % = good, carbon Steele susceptible)
6. temperature (200-400 = susceptible)

Question 4

How can Operations support the FAC program?

Answer 4

Maintain plant systems in a Normal Alignment

Notify FAC program owner when plant not in Normal Alignment

Perform OP C-1, Secondary Plant Efficiency and Safety procedure

Question 5

What are the four key elements to the DCPP FAC Program?

Answer 5

1. Analysis - susceptibility analysis, modeling
2. Inspection - (UT, RT, visual)
3. Replacement Materials - (alloying reduces FAC, Chromium, copper, molybdenum)
4. Fitness for Service Analysis - (evaluate continued service, inspection interval, replacement scope)