Dropping a large three metre stainless steel container from a great height might seem like a bizarre concept, but it’s all in a days work for the PFR project team.
Storage of the spent fuel from the former fast reactor needs to be safeguarded from all potentially hazardous conditions. In order to prove the robustness of the 100kg container a replica model was subjected to a computerised simulated drop followed by an actual six and a half metre drop in the new NES Engineering Ltd off-site test facility at Bower in Caithness.
This phase of the project also included the design and manufacture of a unique remote orbital welding system adapted to remotely seal the container lids from within the PFR caves and to leak test the weld to ensure the container is fully sealed.
The £400k contract was awarded to Nuvia who subcontracted the manufacture and testing of the containers to local firm NES Engineering Ltd, who also manufactured the orbital welding equipment.
“Managing the fuel legacy safely and securely on behalf of the Nuclear Decommissioning Authority is a crucial part of the site closure programme,” explained Simon Coles, PFR decommissioning manager.
“These containers and associated equipment are vital to the fuel strategy for the Dounreay site and for the decommissioning of PFR. The project was delivered to time and cost, which is a credit to the team and all contractors involved.”
On completion of the tests the equipment will be shipped to Dounreay for mounting in the reactor hall cave mock up. Remote assembly trials will be carried out on the welding station to ensure it can be assembled within the confined cave environment and to train operators to use the equipment in safe and clean surroundings.
The irradiated fuel will be packaged into the new containers for long-term storage and held in an on-site facility pending a decision for re-use or management elsewhere.
Dounreay will require anywhere from two hundred to one thousand of these fuel storage containers during the decommissioning of the site.
Diagram shows a 3D image of the Remote Orbital Welding System (ROWS) as it will appear in the IFC, showing an irradiated fuel container in place ready for welding