Page 346 - Beyond Decommissioning

322 Beyond Decommissioning

indicators at the site boundaries. The removed waste was transferred to a containment
cell subject to continuous air filtration. All drains, roads, foundations, and other struc-
tures were surveyed and removed as waste or processed for reuse. All bagged wastes
were routed through a waste assay facility on the SSA. A representative sample from
each bag was taken during filling and the wastes were monitored during filling. Sam-
ples were analyzed for metals, organic chemicals (gas chromatography–mass spec-
trometry), volatile organic compounds, PCB, and total alpha-beta activity. Bags
suspected of containing RAW were rotated on a turntable in front of a calibrated
high-resolution gamma spectrometry system. The combination of these measurements
was used to decide the appropriate waste route, for example, either for shipment to
landfill or for LLW disposal. Although the work was contracted, the UKAEA
maintained close supervision. In terms of waste management, the following summary
can be given:

14,000m of wastes that exceeded a clean-up target were disposed offsite mainly to
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licensed landfill (a small portion was incinerated).
230m of low-level RAWs disposed of to the UK Low-Level Waste (LLW) Repository.
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4500m of scrap and unsuitable inert materials were removed from the site to landfill or
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recycling.
250,000m of soils were sorted through in total.
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In 1989, chlorinated hydrocarbons were detected in the aquifer underneath the SSA.
Investigations revealed that the chemical pits on the SSA had polluted the aquifer
under and around the SSA to above drinking water limits. A program of monitoring
the groundwater and a management strategy was established in agreement with the
regulatory authorities. In 1994, a pump and treat groundwater plant was installed.
Until the end of the remediation project, this system had removed 400kg of contam-
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inants diluted in 2.1Mm of water. The treated water was reinjected into the aquifer.
This plant was eventually discontinued on the basis of costs vs environmental benefits.
The phases of the remediation project can be summarized as follows:
l Groundwater characterization: 1989–94
l First physical investigations into the burial pits: 1992
l Post-operational cleanup of primary contamination: 1994–96
l Detailed characterization: 1995–97
l Environmental assessment and consultation process: 1997–98
l Groundwater treatment by “pump and treat”: 1994–2002
l Main clean-up works for the site and validation: 2000–2002
Some techniques to involve stakeholders were:
local liaison committee briefings,
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addresses to the parish council,
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public meetings,
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a regulators forum,
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media interviews,
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l project newsletters,
l site tours, and
l personal dialog.