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4.1.2 WEAR AGING

Wear aging of the valves was performed in two stages. The first 4,000 cycles were done while thermal aging the valves with the temperature adjusted to 70 °C (158°F). The inlet pressure on the 2A, 2B, and 2C specimens was also adjusted to 100 psi. The inlet pressure on valves 11A, 11B, and 11C specimens were also adjusted to 150 psi. The remainder of the 36,000 wear cycles was then performed at 24 °C (76 F) and 100 psi inlet pressure followed by the Post Wear Aging Baseline Testing. At the conclusion of the wear aging, baseline tests were performed.

4.1.3 PRESSURIZATION AGING

At the conclusion of the wear aging phases the test valves had their inlet and cylinder ports plugged so as not to subject them to atmospheric pressure during the containment pressurization aging phase. The valves were then exposed to pressurization cycles between 0 and 80 psig in two stages. The first stage was one 24-hour dwell at a simulated atmospheric pressure of 80 psig, followed by 14 cycles from 0-80 psig, with a three-minute, minimum, dwell at 80 psig. All valves were de-energized during this phase of testing. Both external leakage and seat leakage were checked at the conclusion of this test.

4.1.4 RADIATION AGING

At the conclusion of the pressurization aging the test valves were all subjected to baseline tests and sent to Isomedix, Inc. for the radiation aging portion of the program. The simulation consisted of exposure to a cobalt- 60 source of gamma radiation with an average energy of 2.5 Mev. The 2A and 11A and 2C and 11C specimens were exposed to at least 20 megarads and the 2B and 11B specimens were exposed to at least 40 megarads. Pipe plugs were installed in the pressure, cylinder, and exhaust ports of the valves. The valves were maintained de-energized during this exposure period. At the completion of this simulation the valves were returned to the ASCO facility and subjected to a baseline test.

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