Appendix CRF - Part 3 - Northamptonshire County Council

8.3 Pre-Closure – not expected to occur
Dropped Load of Waste
Dropped Load
8.3.1 The dose criteria are the legal limit to workers of 20 mSv/yr, the site criterion of 1
mSv/yr for workers, the dose guidance level of 0.02 mSv/yr for the public and the
dose constraint for the public of 0.3 mSv/yr.
8.3.2 The impacted groups during the pre-closure phase are the public and workers.
8.3.3 The scenario is not contained within the SNIFFER model and has been
separately addressed in Annex C, which is a radiological risk assessment for
occupational exposure completed by the HPA.
8.3.4 The conclusion is that with appropriate precautions the worker exposure can be
kept with the site criterion under the unlikely circumstance of a dropped container
which gave rise to a release.
8.3.4 This scenario is not used to constrain landfill capacity.
8.3.5 To augment the calculations in Annex C the following table gives exposure to
both workers and the public under the following assumptions using the UKAEA
dropped load methodology from the safety assessment handbook (ref 22).
8.3.6 The assumptions are:
- A one cubic metre flexible container of wastes is dropped and spills 10%
of its contents through broken seams.
- The bag is filled with a dry solid.
- The bag contains the maximum concentration of a single nuclide at 200
Bg/g.
- The bag weighs 1 tonne.
- The distance to the nearest public is 50m and the event duration is 30
minutes.
- The worker remains very close to the dropped waste without taking
precautions or retreating for at least 30 minutes.
- The atmospheric conditions are worst case, still conditions.
Application for disposal of LLW including HV-VLLW under RSA 1993,
for the East Northants Resource Management Facility:
Supporting Information
July 2009
62
WS010001/ENRMF/CONSAPPCRF 381