For Velan, which has been associated with the nuclear industry since 1950. Valve testing is already a deeply ingrained part of serving t...
For Velan, which has been associated with the nuclear industry since 1950. Valve testing is already a deeply ingrained part of serving the industry. After the recent woes in japans nuclear industry caused by the earthquake and tsunami earlier this year, Velan on its 60th anniversary has taken valve testing for nuclear applications to higher standards making them earthquake safe.
Velan put a team of employees to carry out seismic testing of a 18” 600# parallel slide main steam isolation valve with gas over oil actuator at one of the worlds largest seismic testing facilities at Wyle laboratories in Huntsville, Alabama. Velans first part of the test was resonance search where the valve is subjected to low level sinusoidal vibration in one direction at a time to detect its resonance frequencies. The objective is to obtain higher natural frequency than the frequency of an earthquake vibration so that the equipment will not resonate during an earthquake. The second part of the test was earthquake simulation which is a more vigorous test. Velan carried out this test in two parts viz; the OBE and the SSE. The OBE simulates what would happen in a standard earthquake and the SSE simulates what would happen in a catastrophic earthquake of much higher intensity. Velan achieved the much difficult acceptance criteria of results. The first being no physical damage to the equipment as a whole and its functional operation after the test. The second being the valve was made to shutdown during simulation of both these tests and it had to close between 3 to 5 seconds. Velan yet again setting new standards for the nuclear valve industry.
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