Appendix CRF - Part 3 - Northamptonshire County Council

EAST NORTHANTS RESOURCE MANAGEMENT FACILITY
IONISING RADIATIONS REGULATIONS 1999
1
VERSION 3, 14 July 2009
RADIATION RISK ASSESSMENT FOR LLW WITH A SPECIFIC ACTIVITY UP TO
200Bq/g
1 SCOPE AND DEFINITIONS
1.1 INTRODUCTION
The East Northants Resource Management Facility (ENRMF) operated by Augean plc is
intending to dispose of low level radioactive wastes (LLW) with a specific activity of up to
200Bq/g. An application under the Radioactive Substances Act 1993 has been prepared, and
this includes an assessment of the potential radiation exposure of workers and members of
the public. In addition to this, the Ionising Radiations Regulations 1999 (IRR99) require that a
radiological risk assessment is undertaken for any work involving ionising radiation.
Specifically, Regulation 7 requires the radiation employer (Augean plc) to carry out a prior risk
assessment before commencing work with radioactive materials at the ENRMF site. This
document is intended to meet the requirements of this Regulation in relation to the operational
phase of the controlled burial operation.
1.2 RADIOACTIVE MATERIALS AND RADIATION HAZARDS
The type and quantities of radioactive materials that may be accepted at ENRMF are
described in the RSA93 application and supporting documents. In brief, the application
includes a range of potential radionuclides from nuclear and non-nuclear practices (including
radionuclides of natural origin) with a maximum total activity concentration of 200 Bq/g. This
assessment pessimistically assumes that the waste received contains radionuclides at the
maximum activity concentrations, which is unlikely to be the case in practice.
The radionuclides considered emit a combination of alpha and beta particles and gamma
rays. The handling of these materials can potentially give rise to a radiation hazard from:
- external gamma exposure from proximity to the waste (either during handling waste
containers or occupancy of the disposal areas);
- internal radiation exposure from the inhalation of contaminated dust (air contamination)
arising during the work;
- internal radiation from the transfer and inadvertent ingestion of material (surface
contamination) during the work; and
- internal radiation from any contaminated wounds incurred during the work.
This risk assessment focuses on the exposure of workers and other persons visiting the
ENRMF site. The potential radiation exposure of persons off-site (i.e. members of the public)
from a range of exposure pathways has been considered in detail in the RSA93 application.
This demonstrated that the maximum dose to a member of the public is expected to be
below 0.02 mSv per year 1 . This is well below the relevant IRR99 dose limit of 1 mSv per
1 A higher dose of up to 1 mSv was associated with accidental (public) intrusion into the
landfill. This is a post-closure scenario and is beyond the scope of this risk assessment.
WS010001/ENRMF/CONSAPPCRF 642