CORROSION PRODUCT SAMPLERS

Corrosion Product Sampling
In addition to the impact of corrosion on the performance and reliability of power cycle components such as feedwater heaters and condensers, release of corrosion products from such components and their deposition in turbines and steam generating equipment frequently has led to losses of power generating capability at fossil and nuclear power plants. Since grab sampling and analysis approaches generally will not yield accurate concentration data because of the nature of the corrosion product transport process, application of integrating sampling techniques is mandatory if corrosion product transport and deposition rates are to be quantified (NP-5056-SR).

Product Description
Single and dual channel corrosion product samplers, each available with or without sample coolers. Additionally, all samplers include bypass flow capability. This configuration, as illustrated in Figure 1, provides the ability to process a sample from any point in the cycle while maintaining a high sample line Reynolds number via the bypass system.

A 0.45 mm filter is generally used to collect filterable species from a continuous sample flow with a cation ion exchange membrane inserted below the filter to collect soluble cationic species and possibly colloidal species passing through the 0.45 mm filter.

With a sample flow of 100 ml/min for 24 hours, the membrane packet accumulates the impurities present in a 144-liter sample. Pressure regulation is provided to maintain a constant sample flow as the pressure drop across the membranes increases with time. The flow Totalizer furnishes an accurate value for the total sample volume of the period.

Applications
As stated in the PWR Secondary Water Chemistry Guidelines (EPRI NP-5056-SR): “This sample collection method allows long-term averaging of corrosion product concentrations thereby providing a firm basis for performing mass balances around specific components, e.g., it is possible to identify major sources of corrosion products within the feedwater system.”

Features

• High bypass flow capability (up to 2.2 liters/min.).
  
• Pressure regulation downstream of the filter holder to maintain constant sample flow. As a result, constant sample flow is assured as the differential pressure across the filter membranes increases with time.
  
• Sample flow totalizing (mechanical with ±3.0% accuracy).
  
• Samplers provided in cabinets with clearly illustrated flow schematic on panel.
  
• Sample inlet conditions: up to 3000 psig and 500°F (110°F on samplers without coolers); higher-pressure and temperature capability available on request.
  
• Filter holder connections are Cajon® VCO fittings for easy use and long life.
  
• Inlet and outlet connections are located on a rear bulkhead panel.
  
• Rack-mountable models are available.
  
• All fittings and valves are Swagelok® family components.
  
• When a sampler is supplied with cooling capability, the cooler(s) are mounted inside the cabinet and connected with stainless steel tubing to 1/2" Swagelok® bulkhead fittings on a rear panel ready for connection to the cooling water supply.
  
• Samplers do not require electrical power. This eliminates the need to install an electrical supply or to be concerned with battery replacement.
  
• Sampler can be easily connected to analyzers downstream.
  
• A high temperature, high-pressure inlet isolation valve is provided on the panel. Hence, other than the process root valve, no other isolation valves are needed. This conforms to recommended corrosion product sampling practice, e.g. minimize the number of valves between the process stream and the filter housing.
  
• All valves, regulators and fittings are stainless steel (Type 316). All tubing is seamless SA-213 Type 304 stainless steel.
  
• Filter inlet isolation is accomplished with a 1/4 turn Whitey® Series 33 ball valve.
  
• Samplers are mounted in painted steel cabinets with side handholds.
  
• Approximate cabinet sizes and weights for the current models are as follows:
  100 Series: 10-7/8”W x 15-3/4”H x 14-1/2”D;
  51 lbs with cooler; 35 lbs without cooler
  200 Series: 20-3/8”W x 15-3/4”H x 14-1/2”D;
  100 lbs with coolers; 68 lbs without coolers