Submarines

There are seven redundant nuclear submarines laid up floating at Rosyth and current operations are focused on one-year, six-year and twelve-year maintenance routines for each submarine to ensure they are kept in a safe state and that they will be in a condition suitable for their eventual decom­missioning. The strategy for decommissioning the UK ’s fleet of nuclear submarines was the subject of a consultation exercise carried out in late 2011/early 2012 (MoD, 2011). No date for deciding on the chosen strategy has been made but there are two significant conditions which will affect the decision and its timing. Firstly, decommissioning will not commence until a storage solution for the ILW arising has been agreed. This is a joint MoD and NDA programme in itself. Secondly, berthing space for laying up redun­dant submarines will be full by 2020, so if decommissioning has not started, then further berthing facilities would be required. The current favoured option in the consultation is that the seven laid up submarines at Rosyth would be decommissioned there, but none of the submarines which are operational at present would go to Rosyth for decommissioning.

In 2000, a joint MoD and Babcock project team decided that the nuclear support facilities that would become redundant in 2003 should be decom­missioned with the objective of de-licensing the nuclear site area of 0.83 ha to allow future industrial use. The first operations, which took four years, were to characterise the radioactive contamination, agree on monitoring protocols with the regulators and obtain the necessary authorisations from SEPA. For thoroughness in characterisation, retired employees were inter­viewed for their knowledge of historical discharges or spills, health physics logbooks were checked and the GPS-linked ‘Groundhog’ monitoring system was employed.

Rosyth has an active waste accumulation facility (AWAF) for storing LLW and ILW. It also has a LLLE outlet from the end of one of the dock’s piers. Monitoring of the sediments in the tidal and non-tidal basins detected no significant radioactivity.

The first phase of decommissioning and demolition of redundant facilities was undertaken by contractors and completed in 2009 with 99% recycling of non-asbestos building materials. This has led to low volumes of LLW requiring disposal at LLWR. Contaminated metals were authorised by SEPA to be sent to Studsvik AB in Sweden for treatment. 96% by weight was recyclable by Studsvik and one tonne of LLW was received back which was disposed of at the LLWR. A major facility decommissioned and demol­ished was the health physics building which contained the LLLE treatment plant. As LLLE treatment is a continuing requirement, a mobile unit has been procured.

The ILW waste from the decommissioning to date is organic ion exchange resin which is being stored in AWAF in 1.2 m3 transport container tanks. The strategy agreed with regulators and LLWR is to condition these resins in cementitious grout directly in one-third height ISO containers. The mon­olithic wasteform is LLW which is acceptable for disposal at LLWR. On this basis, the AWAF could be closed in 2016.

The lifetime packaged LLW disposed of at LLWR is estimated to be around 183 m3.

Decisions on delicensing are in abeyance awaiting the determination of the strategy on the SDP.

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