Out-of-reactor feasibility studies of hydrostatic-type venting devices for individual fast reactor fuel pins have been made. The following features were common to all of the devices tested:

  1. absence of moving parts
  2. independence of capillarity effects
  3. compactness
  4. small effect on coolant pressure drop
  5. standard materials and techniques of fabrication
  6. inherent safety.
The tests, run between June 1968 and May 1969, verified that the preferred double capillary tube venting device, named DISCA, operated as designed under both steady-state and transient conditions. In-reactor tests of this and other venting devices are in progress.