Equipment Qualification
Equipment qualification ensures hardware can survive the destructive forces exerted on it from normal plant operations, worst-case scenario accidents, and the forces of Mother Nature. Qualification testing may include any combination of thermal aging, radiation testing, EMI / RFI testing, LOCA testing, seismic testing, and software V&V.
Nuclear plants, like conventional fueled plants, offer up some rather harsh environments for equipment. High humidity and ambient temperatures are common, as is the presence of electro-magnetic radiation radio-interference. Equipment that can easily last forty years under ideal conditions may last only a few years in a harsh environment before components need to be replaced. And some equipment may not function at all if subjected to the extremes of a loss of coolant accident or electro-magnetic pulse created by the nearly start of a large motor.
One of the challenges of qualification testing is determining the worst case set of parameters (design-basis event) the equipment can be subject to and then proving it can operate properly before, during, and after being subject to those parameters. How do we prove an actuator will function after being subject to 130°F for twenty years without the test actually taking twenty years? We may determine that subjecting the actuator to 150°F for four weeks provides the same level of destruction to the soft-parts such as O-rings and seals.
When qualification testing requires equipment to be subject to high temperature, radiation, LOCA, and seismic testing, all of these tests are run on the same sample(s) in series with seismic testing performed last. If at any point the test specimen fails to function properly, all tests must be reperformed. Seismic and LOCA testing is especially difficult because the equipment must actually function during the test.
Extremely large equipment can sometimes be qualified by analysis. Choosing between actual tests and analyses is often a function of the cost between the two, but may also be determined by whether there is test equipment available large enough to perform the test.
NLI generally performs all qualification testing in-house with the exception of radiation testing. Equipment qualification frequently requires modifications to equipment or certain materials to be changed. It is imperative to work with an organization such as NLI that has the engineering resources and experience to know when to make these modifications and parts replacements before expensive and time consuming tests are performed.