Current Arrangements and Requirements for the Conditioning, Packaging and Storage of Intermediate Level Radioactive Waste: Joint RWMAC/NuSAC Report

6. NIREX AND THE LETTER OF COMFORT SYSTEM

6.1 This chapter starts by explaining the purpose and nature of the Nirex Letter of Comfort (LoC) system. It then discusses its relevance in the light of the 1997 RCF decision and uncertainty over policy for the long-term. This is followed by a review of the operation of the LoC system and ways of improving it. The latter includes consideration of the need for greater "regulatory assurance" of the disposability of conditioned waste forms.

The Letter of Comfort system

6.2 Nirex is a body funded by financial contributions from the UK nuclear industry. Since the March 1997 RCF planning decision, Nirex has scaled down its operations, but has retained a research and advisory role to industry on the conditioning and packaging of ILW. This includes a system of endorsement that packaged wastes will meet future waste management requirements, including potential disposal. This is known as the LoC system. The operation of this system constitutes a key aspect of Nirex's core business and the company retains the necessary expertise to operate the system.

6.3 Nirex packaging advice is based on standards and performance specifications that have been developed by the company ¹². These encompass:

• definition of a standard range of containers for packaging of the ILW (although there is acknowledgement that, in some exceptional circumstances, non-standard packages may need to be used);
• specification of appropriate waste package performance and data recording requirements;
• independent assessment of waste producers' plans for the conditioning and packaging of their ILW, and provision of advice to guide packaging design, research and development; and
• independent assessment of all associated quality assurance arrangements.

6.4 Nirex's packaging advice is also linked, in integral fashion, to its Phased Disposal Concept ¹³. This is a Concept that considers the progress of ILW through: conditioning and packaging; transport to a deep underground repository; emplacement in the repository; a period of monitoring during which the waste would be retrievable in a relatively straightforward manner; and, finally, backfilling and sealing of the repository.

6.5 Nirex produces detailed advice on the suitability of specific packaging proposals and conditioning plant designs following a formal assessment and review process. Letters of Advice (LoA) are issued as a result of this process, identifying outstanding issues and requirements for additional information or research. They may also include recommendations for changes to the conditioning process or package. When proposals meet Nirex's requirements - based on compatibility with its Phased Disposal Concept - it will endorse the proposed approach through the issue of a LoC to the waste producer.

6.6 Nirex seeks to issue LoCs in three stages:

• Conceptual: when a waste producer's packaging concept is judged to be compatible with the Waste Package Specifications and the Phased Disposal Concept.
• Interim: at project pre-commitment stage (i.e., before construction of a plant), when the intended product from the designed packaging process is assessed to be compatible with Nirex standards and advice.
• Final: at the pre-operational stage, when the intended product from the constructed packaging plant is judged to be compliant with Nirex standards and advice.

6.7 In issuing a LoC, Nirex is not guaranteeing that the waste packages will be suitable for ultimate disposal, but is seeking to provide a high degree of confidence that they will be suitable for disposal in a future repository.

6.8 Although there is no regulatory requirement for a waste producer to obtain a LoC from Nirex, NII will not normally permit a waste packaging plant to operate until the licensee has done so. The LoC system is also formally recognised in the guidance from the regulators described previously ^10,11.

Relevance of the LoC system in the current situation

6.9 There are in essence two questions of relevance to address. The first is fundamental: is it still relevant to operate a system which seeks to ensure the disposability of waste forms? The second question approaches the issue of relevance from a different perspective: how relevant is the LoC system to a wider range of long-term management options?

6.10 RWMAC/NuSAC consider that in principle there is a clear need for a system that seeks to safeguard the disposability of conditioned waste forms, so that disposal options are not foreclosed for future generations. Indeed, the Committees consider that the need for such a system has been brought into sharp focus by the 1997 RCF planning decision, and by NII's emphasis on the early conditioning of wastes. The basic principle of seeking to safeguard disposability is also supported by the regulators and by the waste producers.

6.11 With regard to the wider applicability of the LoC system, Nirex informed the joint study that its advice was generic to various underground disposal options:

"Nirex .... has always been careful to ensure that its specifications were generic - that is, not dependent on the final development of a repository facility at Sellafield. The specifications and guidance were based upon Nirex safety assessments and naturally took cognisance of ongoing Nirex studies, but were not explicitly based on the Sellafield site specific design studies and investigations in order to provide robustness to uncertainty."

6.12 In addition, Nirex stated that it was assessing whether its advice would be significantly different if underground disposal were not pursued and other long-term management options were adopted. It added that:

"Our initial view suggests that the Nirex specifications and standards (and hence the advice) are robust to a range of possible management options .. including those identified in the Government consultation document (MRWS).

According to Nirex, this includes extended above ground storage, extended underground storage, sea disposal, sub-seabed disposal, and deep borehole disposal, but not disposal in outer space, or partitioning and transmutation.

6.13 RWMAC/NuSAC consider that it is reasonable to expect that Nirex's advice is robust to extended storage options, not least because disposal requirements have to address much longer timescales, and introduce a range of additional considerations. We also note NII's view that Nirex's advice is generally consistent with the achievement of passive safety (see chapter 8). However, when asked to provide copies of its assessments of the robustness of its advice to a range of options, Nirex replied that these are ongoing and have not been finally reported (but that they include literature and expert review of research and development and operating systems). In view of the current uncertainty over long-term policy, RWMAC/NuSAC consider it important that Nirex publish its assessments at an early date so that claims for the wider applicability of its packaging advice can be reviewed and established.

Nirex views on the operation of the LoC system

6.14 As explained above, Nirex seeks to implement a three stage LoC system. However, it pointed out that:

"Historically, we have made our input to waste producers close to the "back end" of their decision-making process regarding the choice of a conditioning and packaging process. Nirex is frequently asked for its advice after alternative options have been evaluated by a waste producer, some development work undertaken, and a preferred option selected and put forward (e.g., immediately prior to start of detailed plant design or construction)."

According to Nirex, seeking advice at a late stage can lead to difficulties. Nirex contrasts this to cases where it has been involved in the preliminary stages of choosing a conditioning and packaging process, which have enabled solutions to be developed which avoid the possibility of reworking, potentially saving waste producers time and money. Nirex notes that a number of waste producers have recognised the value of an early input from Nirex.

6.15 Although welcoming the recognition given to the LoC system in regulatory guidance, Nirex recommended to the joint study that the system could be strengthened in the first instance by establishing meetings between Nirex, NII and EA/SEPA at an early stage. It added that making Nirex a "statutory consultee" within the licensing process could "further ensure that the long-term is made visible to stakeholders and decision-makers and is taken into account by all parties". These proposals are considered further below.

Regulator views on the operation of the LoC system

6.16 NII informed the joint study that it needed to be confident that ILW that is packaged now will be suitable, "so far as it is reasonably practicable, for long-term interim storage and ultimately disposal in a repository". To this end, NII stated that Nirex is providing an important service to the licensees. However, NII added that:

"It is NII's experience that failure to obtain an LoC on a required timescale can impact on safety related operations on the nuclear licensed sites. This can lead to situations where the need to address an immediate safety issue must be balanced against the risk of proceeding without an LoC."

In order to avoid such situations, NII argues that Nirex and the waste producers should operate the LoC system to well-founded programmes, so that technical problems can be addressed by early dialogue between the licensees, the regulators and Nirex. This view reinforces Nirex's call for early involvement.

6.17 Nonetheless, NII also pointed out that where technical problems were unlikely to be resolved on the necessary timescale, it "may find it justifiable for licensees to place radioactive waste in intermediate storage conditions, that leave open the options for eventual packaging, but which represent a significant improvement in the degree of passive safety". Hereafter in this report, such an approach is referred to as an "interim packaging" arrangement.

6.18 Finally, NII drew attention to a further concern: "as the main shareholders of Nirex are the major licensees its ability to provide and sustain independent advice could be questioned, and this could influence its approach when there are issues to be resolved between the company and licencees."

6.19 EA informed the joint study that Nirex's role is a useful one, based on its unique expertise. Nonetheless, EA wishes to see additional "regulatory assurance" of the disposability of packaged ILW. EA explained that there were a number of reasons for this view:

• to overcome difficulties that EA has experienced in obtaining early information about conditioning proposals;
• to enable EA to scrutinise conditioning proposals for wastes which fall outside Nirex's current experience;
• to introduce public transparency in the development of conditioning and packaging programmes (which it argues would help lay the ground for increasing public confidence in any proposals for a new repository programme); and
• to help overcome any concerns that Nirex could in principle be compromised in the future because of its shareholder arrangement.

6.20 EA had previously expressed the view that it should be given a new statutory power over the storage of radioactive wastes on licensed nuclear sites in order to resolve these concerns ¹⁴. EA argued that existing formal mechanisms for provision of information to the Agency (via NII) worked up to a point, but did not provide early enough or sufficient information. The Agency appeared to doubt that improved non-statutory routes could remedy the situation. This issue is discussed further below.

6.21 SEPA informed the joint study that the LoC system provided useful "indicators that the system in place to package ILW is ultimately suitable for disposal". Although SEPA was not seeking a new statutory power over storage, it was of the view that it would be difficult to regulate the final disposal of ILW without being able to exert some regulatory influence over the potential environment impact of ILW conditioning and packaging.

Waste producer views on operation of the LoC system

6.22 The waste producers' contrasting views on the operation of the LoC system were as follows:

"(The) .. Nirex role should be one of advice, not veto on projects. The regulators views on whether Nirex LoCs are mandatory are not consistent ... LoCs work well if used in the right context and the limitations are recognised. They bring an appropriate discipline to considering a treatment route by focus on the technical factors ... Nirex should not be regarded as a third regulator, rather a means of providing advice with a view to ensuring a common approach across all waste producers." (BNFL)

"BE to date only has direct experience arising from the original LoC process (pre 3 stage). The concept is understood and recognised as being helpful, but the caveats associated with it limit the worth and current process is bureaucratic. The costs and time required are considered high relative to the benefit." (BE)

"UKAEA believes that the Nirex letters of comfort and letters of advice system works well ... UKAEA has developed, and agreed with Nirex, a structured format for the submissions for LoCs. The use of a single point of contact .. allows UKAEA to learn from previous advice and submissions and apply this knowledge to future packaging strategies .. The early interaction with Nirex can help to define development programmes and target development work to meet Nirex requirements .. The main area of concern is that Nirex does not apply a holistic approach." (UKAEA)

"AWE has not had enough contact with Nirex to have a particularly strong corporate view of its organisation or the Letters of Comfort/Advice process". (AWE/MoD)

6.23 The waste producers also informed the joint study of a number of specific examples where difficulties had arisen in reaching agreement with Nirex and/or the regulators on conditioning and packaging. These include issues associated with: fissile limits, the long-term behaviour of iodine-129, graphite Wigner energy, and the use of superplasticisers.

Improving the operation of the LoC system

6.24 As outlined above, various suggestions were made to the joint study for ways of improving the operation of the LoC system. These include:

• operating the LoC system to well-founded forward programmes;
• a commitment to early discussions between the waste producer, Nirex, NII and EA/SEPA;
• ensuring that Nirex is not regarded as a quasi-regulator, but as a source of expert advice;
• making Nirex a statutory consultee within the licensing process;
• giving the environment agencies a new statutory power over the storage of radioactive wastes; and
• where difficulties cannot be resolved to necessary timescales, allowing the adoption of interim packaging arrangements.

6.25 RWMAC/NuSAC agree that the LoC system should be operated to well founded forward programmes, with a clear commitment to early discussions between key stakeholders, including Nirex (or successor organisation) and the environment agencies. However, the Committees are not convinced of the need for statutory changes to achieve these and related objectives.

6.26 RWMAC/NuSAC agree that the early and sustained involvement of Nirex (or successor organisation) is important for the timely provision of packaging advice and enabling long-term requirements to be properly considered. The Committees consider that this could be achieved by formally stating that such involvement is a requirement of Government policy. Such an approach would avoid the need for legislation to provide Nirex with the status of statutory consultee. Legislative change would entail various difficulties, given the present industry ownership of Nirex and uncertainty about the company's future. The required statement of Government policy should highlight the importance of the advisory role currently fulfilled by Nirex.

6.27 RWMAC/NuSAC also recognises that the issue of disposability is central to EA's responsibilities and, subsequently, that there is a case for enabling the agencies to provide additional "regulatory assurance" of the disposability of packaged wastes. At issue, however, is the best mechanism for achieving this. The Committees do not favour the EA suggestion ¹⁴ of a new statutory power over the storage of radioactive wastes. This is for two reasons: first, it is unnecessarily broad in conception, with likely impacts on day-to-day operational issues as well as addressing the issue of disposability; and secondly, therefore, it raises concerns about the difficulties that would arise from dual regulation.

6.28 Against this background, RWMAC/NuSAC consider that other approaches to enhancing the role of the EAs should be examined. One approach might be to make each of the three stages of LoC subject to endorsement by the appropriate EA. This could be stated as an expectation of Government policy, and be achieved by formal administrative agreement between NII and the EAs. An alternative approach might be to develop a new statutory role for the EAs based on the issue by them of a "certificate of disposability". RWMAC/NuSAC recommend that such proposals be subject to early appraisal by Government. Whatever proposal is adopted, the Committees consider that policy should give explicit recognition to the potential need for interim packaging, where difficulties in obtaining LoCs cannot be resolved within reasonable timescales (see chapter 7). Attention may also need to be given to means of dispute resolution, presumably at senior management levels.

6.29 RWMAC/NuSAC also observe that if the policy review of long-term radioactive waste management options does not result in the adoption of a policy of underground disposal, the linkage between the LoC system and Nirex's Phased Disposal Concept will become increasingly questionable. In such circumstances, RWMAC/NuSAC recommend that the form, institutional location and presentation of the LoC system should be subject to fundamental review. The purpose would be to develop an appropriate system for the continued safeguarding of the disposability of waste forms, so that disposal options were not foreclosed for future generations. There will also be a need to ensure that the expertise currently located within Nirex is not lost.