Letter of Compliance Studies
The UK Radioactive Waste Management Directorate (RWMD) issue Letters of Compliance (LoCs) to waste producers to give them assurance that packaged intermediate level wastes will meet requirements for disposability if and when a UK waste repository is constructed. The LoCs are only issued after a detailed assessment of the packaging proposals covering a wide range of criteria.
For radiological studies, the requirements are principally for a Nature & Quantities study, a Data Recording study and a Criticality Compliance Assurance document (CCAD). Depending on the stage of submission, these may be combined into a single document of issued as separate documents.
I have been involved in production of the radiological LoC
documents, and supporting documents, for many years, both as author on
behalf of the waste producers and as assessor on behalf of RWMD.
Examples of specific project involvement include:
Trawsfynydd Fuel Element Debris (FED) packaging, in particular the
Data Recording and CCAD documents. The justifications were entwined with
design of the FED assay system, and were a challenge given the
possibility of fragments of fuel being present along with general
contamination arising from the storage periods in the fuel cooling
Hunterston sludge and resin packaging: I wrote supporting documents for estimation of radionuclide inventories & radiological properties, and justification of procedures for data recording.
Sizewell B dry fuel storage studies: I was deeply involved in estimation of the radionuclide inventory and radiological properties of a hypothetical study for dry packaging of PWR fuel.
Berkeley Active Waste Vaults: I have been involved in LoC supporting
work over a period of around ten years, over which time the project has
been re-invented many times. Challenges arose from the very
heterogeneous waste form, the lack of detailed information on
compositions of some of the wastes, the lack of radiochemical data and
many changes to the process design. The assay system changed radically
over the period of my involvement (I like to think that I influenced it
for the better) which impacted on the way in which data were to be
Assessment of LoC submissions to RWMD, including graphitic wastes
from Windscale Pile 1 and Ionsiv resins