Radiation Protection Commissioning of Neutron Beam Instruments at the OPAL Research Reactor

摘要

The neutron beam facilities at the 20 MW OPAL Research Reactor were commissioned in2007 and 2008. The initial suite of eight neutron beam instruments on two thermal neutron guides, two cold neutronguides and one thermal beam port located at the reactor face, together with their associated shielding wereprogressively installed and commissioned according to their individual project plans. Radiation surveys weresystematically conducted as reactor power was raised in a step-wise manner to 20MW in order to validateinstrument shielding design and performance. The performance of each neutron guide was assessed by neutronenergy spectrum and flux measurements. The activation of beam line components, decay times assessments andaccess procedures for Bragg Institute beam instrument scientists were established. The multiple configurations foreach instrument and the influence of operating more than one instrument or beamline simultaneously were alsotested. Areas of interest were the shielding around the secondary shutters, guide shield and bunker shield interfacesand monochromator doors. The shielding performance, safety interlock checks, improvements, radiation exposuresand related radiation protection challenges are discussed. This paper discusses the health physics experience ofcommissioning the OPAL Research Reactor neutron beam facilities and describes health physics results, actionstaken and lessons learned during commissioning.