Steam Turbine and Piping Corrosion and Chemistry
This service offers a set of experimental techniques that determine chemical composition and corrosiveness of steam and early condensate in the utility turbines (including HP and LP PWR turbines), moisture separators, and associated piping. It also offers field-testing of U-bend and fracture mechanics specimens for stress corrosion cracking (SCC), corrosion fatigue (CF), and pitting and sensitive corrosimeters to detect flow-accelerated corrosion (FAC).
Background
Many turbines experience stress corrosion cracking of blades and discs and almost 100% of these turbines experience flow-accelerated corrosion (FAC) of carbon and low-alloy steel components, including turbine discs, seals, and shells (cylinders), extraction, inlet, and cross-under piping, and MSRs.
There are a number of cycle chemistry control regimes, most using organic water treatment chemicals and boric acid. While helping to control corrosion of steam generators, these complex treatments can produce corrosive steam moisture and deposits in the turbine and MSRs.
Description of Service
The following tests are used to be able to determine the root causes of the above corrosion problems, propose water chemistry solutions, and provide data on the rate of damage (which can be used in failure prevention):
Corrosion and FAC monitoring - in-situ in piping Field stress corrosion and corrosion testing of stressed U-bend and fracture mechanics specimens
Figure 1 gives an example of an instrumented LP turbine.
Figure 1. Installation locations of equipment available for LP turbines
