Appendix CRF - Part 3 - Northamptonshire County Council

8.5 Pre-Closure – not expected to occur
Exposure from Fire
8.5.1 The dose criteria are not defined within the guidance on requirements for
authorisation for this scenario but could be taken to be the worker dose target of
1 mSv/yr and the public dose constraint of 0.3 mSv/yr.
8.5.2 The impacted groups during the pre-closure phase are the public and workers.
8.5.3 The scenario is transient and for practical purposes can only occur whilst the
wastes are not covered with the final capping layer. The lack of biodegradable
wastes makes fires very unlikely after the cap is in place.
8.5.4 Furthermore, some of the exposure pathways considered in the SNIFFER fire
model would not arise in practice because intervention would occur. So for
example exposures from any subsequent deposition would be controlled by
remedial activities.
8.5.5 Although an aircraft crash could lead to a fire, the fire would mostly consume
aircraft fuel and wreckage. The main feature of an aircraft impact which could
lead to exposure would be the physical displacement of material and this is
considered in Section 8.3.
8.5.6 The waste in the landfill, the cover materials and the LLW are essentially
incombustible. The current waste acceptance criterion for the landfill largely
excludes organic material and includes a flammability test. As such it is difficult
to conceive that the fire scenario included in the SNIFFER model can occur for
this type of landfill and it has not been utilised to constrain landfill capacity.
8.6 Pre Closure and Aftercare Period – expected to occur
Exposure from Leachate Processing Offsite – Sewage Works
8.6.1 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.
8.6.2 The impacted groups are sewage workers and the public impacted by the
sewage works.
8.6.3 The scenario is addressed in Annex B.
8.6.4 Leachate levels at the ENRMF are maintained by pumping excess leachate to
tankers and transporting this leachate to a water treatment plant at Avonmouth.
An initial assessment of the potential impacts from routine, off-site leachate
management has been made using the Environment Agency’s methodology and
Application for disposal of LLW including HV-VLLW under RSA 1993,
for the East Northants Resource Management Facility:
Supporting Information
July 2009
68
WS010001/ENRMF/CONSAPPCRF 387