Office for Nuclear Regulation

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A review by the Health and Safety Executive's Nuclear Installations Inspectorate of the strategy of Rolls-Rovce Marine Power Operations ltd for the decommissioning of its nuclear sites.

Introduction

This report sets out the findings of a review by the Health and Safety Executive's (HSE) Nuclear Installations Inspectorate (NII), in consultation with the Environment Agency (EA), of the strategy of Rolls-Royce Marine Power Operations Ltd (Rolls-Royce) for decommissioning its nuclear licensed sites. NII is that part of HSE responsible for the regulation of safety on nuclear licensed sites, including radioactive waste management and decommissioning activities. The EA regulates the disposal of radioactive waste from the nuclear sites.

Government policy, set down in the 1995 White Paper "Review of Radioactive Waste Management Policy: Final Conclusions", Cm 2919 [1], requests nuclear operators to draw up strategies for the decommissioning of their redundant plant, including justification of the timetables proposed and the adequacy of the financial provision. Government policy is for HSE, in consultation with the environment agencies, to review these strategies on a quinquennial basis to ensure they remain soundly based. This review is one of the series that HSE is undertaking for the UK nuclear licensees.

Rolls-Royce has provided HSE with a document [2] presenting a summary of its decommissioning strategy; enquiries concerning that document should be made to the licensee.

Background

Rolls-Royce operates two nuclear licensed sites at Raynesway in Derby, on which the work carried out is exclusively in support of the Ministry of Defence's (MOD) nuclear submarine programme. They are:

(i) the Neptune site, which comprises a reactor hall with adjoining fuel storage facilities, radiation laboratories and radioactive waste management facilities and a separate radioactive components handling facility. The low energy reactor is used to develop and prove submarine reactor designs and the radioactive components facility is used to repair and refurbish potentially radioactive equipment.

(ii) the Nuclear Fuel Manufacturing site, which contains facilities for the manufacture of reactor cores and other equipment for naval submarines, and associated maintenance shops and offices.

The future use of the sites is linked to the UK nuclear submarine programme and Rolls-Royce has based its decommissioning strategy on the current programme. The timescales Rolls-Royce assumes for closure of the three facilities are:

Neptune reactor 2013 Radioactive components handling facility 2045 Fuel manufacture plant 2017

After closure, Rolls-Royce proposes to decommission each facility within a period of three to four years. The first step will be to remove all the fissile material and return it to the MOD, then the remaining radioactive material will be removed from the site and disposed of. Rolls-Royce states that its aim is to reduce the residual radioactivity to levels that will allow the sites to be delicensed and thereby released for other use.

In undertaking these reviews HSE aims to assess the proposed decommissioning strategy to determine whether it is adequately comprehensive, technically practicable and appropriately timed. In particular it considers whether the strategy is consistent with Government policy that 'decommissioning should be undertaken as soon as it is reasonably practicable to do so, taking account of all relevant factors', and also that the 'hazards presented by the plant (or site) are reduced in a systematic and progressive way'. It also considers whether arrangements are in place to quantify the costs of decommissioning and to make available funds to undertake the work on the proposed timescales in order to assess 'the adequacy of the financial provision being made to implement the strategy'.

HSE has based this review on the information provided in Rolls-Royce's summary of its decommissioning strategy [2], together with the outcome of discussions held with its staff. The EA has been consulted throughout the review.

Technical Assessment

Rolls-Royce has identified all the liabilities that will have to be addressed and has described the manner in which it intends to deal with them. In terms of the UK's nuclear licensed sites the Rolls-Royce sites are small and contain relatively small amounts of radioactive material. Once the fissile material, which is the property of the MOD, has been removed from the site the hazard will be significantly reduced. The decontamination and dismantling of the remaining equipment and buildings should not pose any particular hazard. As a result HSE has no reason to believe that decommissioning of the facilities will present any significant technical challenges. Decommissioning will generate a quantity of low-level radioactive waste and Rolls-Royce will need to ensure that there is an authorised disposal route for this material.

With respect to timing, the strategy is based on early decommissioning following final shutdown of the facilities. Three to four years is allowed for the decommissioning of each facility, but no further delay is to be introduced. These timescales are considered to be consistent with Government policy that decommissioning should be carried out as soon as reasonably practicable. Rolls-Royce currently assumes the nuclear submarine programme will run well into the future, but should this not be the case, and earlier closure is necessary, then the strategy is flexible enough to be applied at any time. The sequence in which Rolls-Royce proposes to remove the radioactive material is logical and consistent with reducing the hazard in a systematic and progressive way.

Rolls-Royce acknowledges that prior to decommissioning more detailed planning will be required. As decommissioning is not planned to start for at least another 11 years HSE considers that the current level of development of the strategy is reasonable. HSE would expect detailed plans to be progressed such that they are fully developed for the start of decommissioning.

Financial Assessment

Rolls-Royce's cost estimates are indicative values based on its knowledge of similar decommissioning projects. Nevertheless, HSE believes that Rolls-Royce has a broad understanding of the magnitude of the decommissioning costs. MOD has confirmed that it will meet the reasonable costs of decommissioning the facilities. On this basis HSE believes that the current arrangements provide confidence that adequate financial provision will be available for decommissioning, and that decommissioning could be taken forward on a shorter timescale if necessary.

Conclusions

HSE regards the strategy proposed by Rolls-Royce for decommissioning its nuclear sites at Raynesway, Derby to be appropriate at this time. It is technically practicable, consistent with experience on other similar projects, and the timetable is in line with Government policy. Rolls-Royce has prepared cost estimates for decommissioning, and MOD has confirmed that it will meet the reasonable costs of decommissioning.

References

[1] Review of Radioactive Waste Management Policy - Final Conclusions, UK Government Cm 2919, HMSO 1995.

[2] Strategy for the Decommissioning of the Two Nuclear Licensed Sites Operated by Rolls-Royce Marine Power Operations Limited, RRMP 19524, Issue 1, September 1999.


Published on HSE website 22 May 2002