Novel cryogenic engineering solutions for the new Australian Research Reactor OPAL

In August 2006 the new 20MW low enriched uranium research reactor OPAL went critical. The reactor has 3 main functions, radio pharmaceutical production, silicon irradiation and as a neutron source. Commissioning on 7 neutron scattering instruments began in December 2006. Three of these instruments (Small Angle Neutron Scattering, Reflectometer and Time-of-flight Spectrometer) utilize cold neutrons. The OPAL Cold Neutron Source, located inside the reactor, is a 20L liquid deuterium moderated source operating at 20K, 330kPa with a nominal refrigeration capacity of 5 kW and a peak flux at 4.2meV (equivalent to a wavelength of 0.4nm). The Thermosiphon and Moderator Chamber are cooled by helium gas delivered at 19.8K using the Brayton cycle. The helium is compressed by two 250kW compressors (one with a variable frequency drive to lower power consumption). A 5 Tesla BSCCO (2223) horizontal field HTS magnet will be delivered in the 2nd half of 2007 for use on all the cold neutron instruments. The magnet is cooled by a pulse tube cryocooler operating at 20K. The magnet design allows for the neutron beam to pass both axially and transverse to the field. Samples will be mounted in a 4K to 800K Gifford-McMahon (GM) cryofurnace, with the ability to apply a variable electric field in-situ. The magnet is mounted onto a tilt stage. The sample can thus be studied under a wide variety of conditions. A cryogen free 7.4 Tesla Nb-Ti vertical field LTS magnet, commissioned in 2005 will be used on neutron diffraction experiments. It is cooled by a standard GM cryocooler operating at 4.2K. The sample is mounted in a 2nd GM cryocooler (4K–300K) and a variable electric field can be applied. © 2008, American Institute of Physics

Keywords

OPAL Reactor, ANSTO, Cryogenics, Research reactors, Engineering, Reactor instrumentation

Citation

Olsen, S. R., Kennedy, S. J., Kim, S., Schulz, J. C., Thiering, R., & Gilbert, E. P., Lu, W., James, M., & Robinson, R. A. (2008). Novel cryogenic engineering solutions for the new Australian Research Reactor OPAL. Paper presented to the 2007 Cryogenic Engineering Conference and International Cryogenic Materials Conference, 16th – 20th July 2007. In J. G. Weisend, J. Barclay, S. Breon, J. Demko, M. DiPirro, J. P. Kelley, P. Kittel, A. Klebaner, A. Zeller, M. Zagarola, S. Van Sciver, A. Rowe, J. Pfotenhauer, T. Peterson & J. Lock (Eds.), AIP Conference Proceedings, 985(1), 299-306. doi:10.1063/1.2908561