OPAL cold neutron guide in-pile replacement
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Date
2013-10-13
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International Group On Research Reactors
Abstract
The 20 MWth OPAL research reactor has five neutron beam assemblies. These provide cold and thermal neutrons to various neutron guides and associated neutron beam instruments. In 2010 a project was initiated to install a new cold neutron guide, CG2, in one of the assemblies. This installation would allow up to four new neutron beam instruments to be built, significantly expanding the reactor's capabilities. The project concluded in December 2012 with the successful installation of CG2. Each neutron beam assembly has an in-pile plug, a primary shutter and a front cover. Together these constitute the neutron guide's in-pile components, with a total mass of over 12 tonnes. The CG2 installation required the complete replacement of the existing components. This replacement was scheduled to coincide with OPAL's first major shutdown. With a budget of $2.3 million and an expected dose of 50 man.mSv, the CG2 installation was a large and complex task. Work during the shutdown involved over 40 ANSTO personnel and radiation fields approached 1 Sv/h in some areas. Despite this, the installation team received a collective dose of only 10 man.mSv, and the project was completed to budget and within schedule. This paper will outline the details of the project, focusing on lessons learned and recommended practices. Each OPAL in-pile plug has a design life of 10 years at full power operation, and similar replacements will be performed regularly as the reactor ages. It is hoped that this information will be useful for other research reactors planning large capital engineering projects.
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Keywords
Cold neutrons, Reactor design, Neutron beams, OPAL Reactor, Planning, Radiations, Reactor shutdown, Thermal neutrons
Citation
Rownes, T., Eltobaji, A., Bell, M., & Klose, F. (2013). OPAL cold neutron guide in-pile replacement. Paper presented at the 15th Meeting of the International Group on Research Reactors, "IGORR 15", Daejeon, South Korea, 13-18 Oct 2013. Retrieved from: https://www.igorr.com/Documents/2013-DAEJEON/02_1016.pdf