Conditioning involves transforming radioactive waste into a form suitable for handling, transport, storage and disposal. This may include immobilisation of radioactive waste, placing waste into containers and providing additional packaging.
Common immobilisation methods include solidification of LLW and ILW in cement, or vitrification of HLW in glass. Immobilised waste could be placed in steel drums or other engineered containers to create a waste package.
Case study
Conditioning – MILWEP concrete
The modular intermediate level waste encapsulation plant (MILWEP) project is delivering visible progress, as well as vital learning for other key work packages.
MILWEP plants are designed to grout waste inside the concrete box and remotely cast the lid to complete the disposal package. Grout and lid casting can be provided in either normal density or high-density concrete depending on the activity of the waste being packaged. Berkeley site utilises normal density grout and concrete. Once curing of the grout is completed, capping grout is then placed followed by casting of the concrete lid to complete the disposal package.
Active commissioning of the Berkeley site MILWEP started in June 2022. The first concrete box filled with ILW was successfully delivered from the reactor two retrievals facility to MILWEP and flood grouting of the box completed. By the end of December 2023, the site had completed a total of 17 concrete boxes and filled five more ready for conditioning through MILWEP.
The MILWEP project has been working collaboratively with NSG for six years developing the design, manufacture, installation, and commissioning of encapsulation facilities for Berkeley, Hinkley Point A and Chapelcross sites. Berkeley was the first plant to enter active commissioning with lessons from that site to be taken forward into future plants planned at the other two sites.
A Waste Programme Senior Project Manager said: “I am delighted with the efforts of the MILWEP team to get us to this point, it has been a massive effort particularly over the last few months. I am also really pleased with the teamwork across the site and the approach of the integrated active commissioning team whose hard work and collaboration has enabled the start of active commissioning at MILWEP.”
The three MILWEP sites are not the only sites within NRS looking to utilise concrete boxes. At Winfrith both the Steam Generating Heavy Water Reactor and Dragon reactor dismantling projects are also taking the learning from the MILWEP project to implement the same process, using where possible the same plant and equipment.