As flagged in our December update we will keep our users and other stakeholders up to speed with developments with OPAL's Cold Neutron Source (CNS)
Significant steps are currently in progress to achieve cold neutron source system availability and reliability in cryogenic mode.
Late last year, ANSTO engaged an Expert Panel to comprehensively analyse the technical issues identified in reviews and studies of the CNS system. That expert review process resulted in a report to ANSTO’s Chief Executive Officer, with recommendations for a staged approach returning the CNS to reliable cryogenic service
In summary, the short-term plan is to bring the CNS into a deterministic and predictable operating regime. The long-term plan is to ensure that the CNS has a fail-safe capability in cryogenic mode within the predictable operating regime. This will mean that, should the plan’s objectives be realised, cold neutrons will be supplied at high availability when the OPAL reactor is operating.
The Expert Panel comprised of local and global leaders renowned for their expertise in CNS system operations, cryogenic system design, project engineering and reactor engineering and operation. A key input to the Expert Panel review was an in depth root-cause analysis, which was facilitated by a global expert in industrial engineering.
It is worth noting the expert concluded the CNS system problem is amongst the most challenging he had experienced.
The recommendations from the Expert Panel now form the basis of a CNS Rectification Project based on short- and long-term interventions to secure reliable supply of cold neutrons for OPAL's neutron beam users.
The CNS Rectification Strategy incorporates a staged approach:
- Short-Term Plan (6 months – July 2013) - Increase the reliability of the two existing helium compressors in cryogenic operating mode. This will be primarily achieved by decreasing the oil injection temperature, optimising the oil flow rate, and the installation of magnetic filters to remove metallic contamination of the oil. In addition the institution of consistent set-up and start-up procedures along with improved on-line instrumentation and diagnostics will ensure consistent configuration control of the helium compressors. During this period system trials will be undertaken to evaluate cryogenic mode performance;
- Medium-Term Plan (12 months – December 2013) - If the Short-Term Plan modifications prove to be successful ANSTO will procure a third compressor to improve operational redundancy and availability. Options for this procurement are currently being investigated, with one option being the replacement of one of the current single air-end compressors with a twin air-end compressor;
- Long-Term Plan (2-3 years - 2015/16) – Replacement of the existing single air-end compressors with new compressor units. This option will deliver an improved design, a higher level of redundancy and more predicable failsafe path;
- Alternative Plan (2 years – 2015) – If the rectification outlined above is unsuccessful ANSTO will institute a program which entails replacement of the current compressors with a new type of helium compressor.
ANSTO remains committed to ensuring a reliable CNS system that is able to deliver reliable cold neutrons. The CNS Rectification Strategy underpinned by the planned approach described above will ensure this objective is realised in the shortest possible time. Again, we appreciate the support from our neutron beam users and stakeholders and thank you for your patience as we solve this non-trivial challenge.
Published: 16/03/2013