Temperature controlled material irradiation in the advanced test reactor

The United States Department of Energy (US DOE) has initiated the developme nt of an Irradiation Test Vehicle (ITV) for fusion materials irradiation at the Advanced Test Reactor (ATR) in Idaho Falls, Idaho, USA. The ITV is cap able of providing neutron spectral tailoring and individual temperature con trol for up to 15 experiment capsules simultaneously. The test vehicle cons ists of three In-Pile Tubes (IPTs) running the length of the reactor vessel . These. IPTs are kept dry and test trains with integral instrumentation ar e inserted and removed through a transfer shield plate above the reactor ve ssel head. The test vehicle is designed to irradiate specimens as large as 2.2 cm in diameter, at temperatures of 250-800 degrees C, achieving neutron damage rates as high as 10 displacements per atom per year. The high fast to thermal neutron flux ratio required for fusion materials testing is acco mplished by using an aluminum filler to displace as much water as possible from the flux trap and surrounding the filler piece with a ring of replacea ble neutron absorbing material. The gas blend temperature control system re mains in place fr om test to test, thus hardware costs for new tests are li mited to the experiment capsule train and integral instrumentation. (C) 199 8 Published by Elsevier Science B.V. All rights reserved.