Decision

GDA Step 1 of the GE-Hitachi SMR: statement of findings full report

Updated 17 December 2024

Applies to England and Wales

Introduction

Purpose

This report sets out the findings of the Environment Agency and Natural Resources Wales following our work in the Step 1 (Initiation) of the Generic Design Assessment (GDA) of the BWRX-300 nuclear power station design.

GE-Hitachi Nuclear Energy International LLC (UK Branch) is the Requesting Party (RP) for the GDA, subsequently referred to as the RP or GE-Hitachi. GE Vernova, Inc. is the ultimate parent company of GE-Hitachi Nuclear Energy International LLC. The RP applied to the Department for Energy Security and Net Zero (DESNZ) for its design to enter the GDA process and. the application was successful. The regulators (The Environment Agency, The Office for Nuclear Regulation (ONR) and Natural Resources Wales (NRW)) were asked by the Minister to begin a GDA for this design. Step 1 (Initiation) of the GDA formally began in January 2024.

Illustration of BWRX-300 SMR. Copyright GE-Hitachi Nuclear Energy International LLC.

About GDA

GDA is a joint project between the environment agencies (Environment Agency and NRW) and ONR. Our GDA process is described in the GDA Guidance for Requesting Parties. GDA means that we assess the acceptability of the environmental aspects of a design, at a generic level, before site-specific applications are made. ONR has an equivalent and aligned process for assessing the safety, security and safeguards aspects of a design, ONR GDA Guidance to Requesting Parties. GDA allows us as the regulators (Environment Agency, ONR and NRW, where applicable) to engage with designers and, where possible potential operators, at the earliest stage, where we can have most influence to ensure people and the environment are protected. This early engagement also reduces future regulatory uncertainty for designers and potential operators.

Joint working with ONR

We work closely with ONR particularly on GDA project management; on the RPs management arrangements and quality assurance for GDA; and on aspects of radioactive waste management. We expect this joint working to continue for the remainder of GDA.

We have:

• agreed that RPs can choose to provide information about their designs as a single, integrated submission, addressing the requirements of all regulators
• set up a Joint Programme Office (JPO) to administer the project on behalf of all the regulators as a single point of contact

Our assessment

GDA is a flexible process with multiple options for outcomes. We carry out GDA in up to 3 steps.

During Step 1 (Initiation), we make agreements with the RP and provide advice on the scope and development of the GDA submission.

In Step 2 (Fundamental Assessment), we examine the RP’s submission at an outline level. Our aim is to identify whether we need any further information, if there are any matters that are obviously unacceptable, or if any significant design modifications may be needed.

Step 3 (Detailed Assessment) is when we examine the submission in detail to come to a preliminary view on whether to issue:

• a Statement of Design Acceptability (SoDA), because we have not found any GDA Issues and we consider that the design is capable of being constructed, operated and decommissioned in a way that complies with our regulatory requirements and expectations, ensuring that people and the environment are properly protected
• an interim Statement of Design Acceptability (iSoDA) - if we have completed our assessments and are happy with the environmental protection aspects, but there are still GDA Issues to be resolved and the RP has provided credible resolution plans for addressing them
• neither an iSoDA nor a SoDA

We will not issue either an iSoDA or SoDA if the design is unsuitable and will not provide the right levels of environmental protection, or if there are GDA Issues but no credible resolution plans.

We will only make our final decision to issue a SoDA or an iSoDA after we have consulted the public and carefully considered the responses we receive.

There are 2 other possible GDA outcomes:

• Step 2 Statement - the RP may stop or pause the GDA at the end of Step 2. At this point, we will publish a GDA Step 2 Statement setting out our regulatory position and our findings from the Step 2 assessment.
• Step 3 Statement - the RP may end the GDA at the end of Step 3 without a SoDA. In this case, we will publish a GDA Step 3 Statement, which will set out our regulatory position and findings following the Step 3 assessment.

We will do this where we have agreed with the RP that the GDA Step 3 can be carried out based on a reduced but still meaningful scope. The Step 3 Statement will include Assessment Findings, where appropriate. Where a Step 3 Statement is the outcome, no public consultation would be carried out.

GE-Hitachi has applied for a 2-step GDA, with a Step 2 Statement as the GDA outcome. The RP is not currently intending to complete Step 3 and is, therefore, not aiming for a Statement of Design Acceptability to be issued at the end of this GDA. The Environment Agency and NRW will not carry out any public consultation.

Environmental regulation of nuclear power stations

The Environment Agency regulates nuclear power stations in England and NRW regulates nuclear power stations in Wales. The Environment Agency supports NRW with regulation of nuclear sites in Wales. NRW participates in GDA where a new nuclear power station design is likely to be proposed for construction in Wales.

The generic design assessment we and NRW carry out is guided by standards and expectations set out in several regulatory regimes. However, our assessment focuses primarily on matters relevant to radioactive substances regulation (RSR).

This is because:

• radioactive waste is generated during the operation and decommissioning of a nuclear reactor and its associated plant
• permitting the disposal and discharge of radioactive waste has, historically, been the area of regulation with the longest lead time for our permitting of new nuclear power stations

Discharge and disposal of radioactive waste from a nuclear site require a permit under The Environmental Permitting (England and Wales) Regulations 2016 (EPR16).

Although GDA is focused towards RSR, we also regulate certain non-radioactive activities at a nuclear site. The discharge of (non-radioactive) aqueous effluents, such as turbine condenser cooling water or from dewatering during construction, also requires a permit under EPR16.

Some conventional plant, for example, combustion plant used as auxiliary boilers and standby power supplies and incinerators used to dispose of combustible waste may require a permit under EPR16. Some combustion plant may also need a permit under The Greenhouse Gas Emissions Trading Scheme Regulations 2012.

The disposal of waste by depositing it on or into land, including excavation materials from construction, and other waste operations may require a permit under EPR16.

The abstraction of water, for example, for cooling or process use from inland waters or groundwater, except in some specific circumstances, requires a licence under The Water Resources Act 1991 (WRA91). Inland waters include rivers, ponds, estuaries and docks, among others.

The construction of new or enhanced flood defence structures or the modification of existing ones requires an environmental permit under EPR16 (previously flood defence consent under WRA91).

In England, the Environment Agency and ONR together form the competent authority for The Control of Major Accident Hazards Regulations 2015. In Wales, NRW and ONR form the competent authority. On-site storage of certain substances may fall under these regulations.

The BWRX-300 design

This section provides a brief outline of the BWRX-300 reactor design. More detail can be found in the BWRX-300 General Description document, publicly available on the GE-Hitachi website. Further information will be placed on the GE-Hitachi GDA website early in Step 2.

Outline of design

The BWRX-300 is a small modular boiling water reactor (BWR) that can generate 300 megawatts (MW) of electricity. BWRs are single circuit reactors, where water is heated as it passes through the reactor core. The resultant steam is dried and passed directly through a turbine before being condensed and returned as water to the reactor core.

Boiling water reactor designs have been in operation for over 60 years and the BWRX-300 is a 10th generation BWR design. It is an evolution of the Simplified Boiling Water Reactor (SBWR) and the Economic Simplified Boiling Water Reactor (ESBWR). The ESBWR has been licensed by the United States Nuclear Regulatory Commission (US NRC) and completed Step 2 of a full GDA in 2008. Neither the SBWR or ESBWR have been built and operated.

The BWRX-300 also has some features in common with the Advanced Boiling Water Reactor (ABWR), such as the fine motion control rod drives (FMCRD), that previously completed a full GDA and was awarded a Statement of Design Acceptability (SoDA) in 2017 by the Environment Agency and Natural Resources Wales.

The BWRX-300 uses natural circulation, with a focus on passive safety. The plant is designed to operate for 60 years, with refuelling every 12 to 24 months dependent on operational decisions. The natural circulation is achieved by the chimney effect from the tall reactor pressure vessel. The reactor vessel is located entirely below ground level.

The reactor uses an existing uranium oxide zircaloy-2 clad fuel type (GNF2) enriched up to 4.95%. Reactivity is controlled by FMCRD by inserting control rods from beneath the reactor pressure vessel.

The BWRX-300 aims to achieve a single globally applicable design, based on the International Atomic Energy Authority (IAEA) safety standards framework. The BWRX-300 design is also currently being put through regulatory scrutiny as part of pre-application licensing reviews in the US and application license reviews in Canada.

Sources, processing and disposal of radioactive waste

Radioactive waste in the form of solids, liquids and gases arise from activities associated directly or indirectly with operating and maintaining the reactor, and ultimately, from decommissioning the plant. The BWRX-300 radioactive waste systems are not novel compared to other BWR designs.

Liquid wastes

The BWRX-300 is designed such that is normally operated with zero liquid discharges, but there may be circumstances where an operator could choose to make liquid discharges, such as to manage water balance or where effluents cannot be made suitable for reuse. However, there are BWRs that do operate for a significant period with no liquid discharges.

Liquid effluents arise from sumps and floor drains, due to leakage or maintenance activities. Normal operational waste streams are collected in tanks and batch treated with filtration and ion exchange before being sampled and transferred to a condensate storage tank (CST) for reuse in the reactor. During refuelling, large volumes of water are used to flood the reactor cavity and refuelling pools. The BWRX-300 has sufficient storage capacity, such that after refuelling, this water can be cleaned for reuse rather than being discharged.

Solid wastes

Wet solid radioactive waste will result from ion exchange resins and filter backwash sludges from the treatment of liquid effluents; these could be low level waste (LLW) or intermediate level waste (ILW). Liquids generated in the solid waste management system will be transferred to the liquid waste management system for treatment and reuse.

Dry solid waste will result from heating, ventilation and air conditioning (HVAC) filters and other operational and maintenance wastes such as paper, rags, clothing, plastics, tools and activated or contaminated components. The solid waste management system will manage, package and store wastes until disposal, off-site. We will assess if this includes appropriate sorting and segregation and waste characterisation for optimised disposal in the UK waste infrastructure.

It is proposed that for GDA, it will be assumed that the waste service offered by the Low Level Waste Repository (LLWR) will be used to dispose of low level waste.

Spent fuel will be cooled in a spent fuel pool (SFP) before being dried and packaged for interim storage, in readiness for ultimate disposal at a geological disposal facility (GDF).

There is also a potential for oily radioactive wastes to be created which would be collected in drums for off-site disposal.

Gaseous wastes

Gaseous effluents occur from the condenser, where non-condensable gases are removed via steam jet air ejectors (SJAE) to maintain turbine efficiency. Gases are passed through a catalytic hydrogen and oxygen recombiner to reduce hydrogen risks and then conditioned to remove moisture before passing through charcoal delay beds, where some radionuclides, especially krypton and xenon isotopes can decay before sampling and routing to the stack for discharge.

Other gaseous waste will result from the building HVAC systems. These gases are filtered using high-efficiency particulate air (HEPA) filters before discharge via the stack.

Non-radioactive waste

Non-radioactive waste is produced from all life cycle phases of a nuclear power station. When operating and maintaining the ‘conventional’ side of a BWR power station this will include:

• combustion gases discharged to air from diesel generators
• water containing water treatment chemicals from the turbine-condenser cooling system and other non-radioactive cooling systems, which can be discharged to the sea, lakes or other water bodies
• oils and any other significant liquids or sludges
• worn-out plant and components
• general waste

The environmental regulators’ process for the BWRX-300 GDA

We (the Environment Agency and NRW) and ONR are using the GDA process to scrutinise GE-Hitachi’s BWRX-300 design and assess its acceptability for use in the UK.

We are carrying out a GDA of the BWRX-300 before it has started construction. This allows us to identify potential regulatory concerns or technical issues early so that GE-Hitachi (the RP) can address them early.

GDA is not a legal requirement, and we are carrying out the GDA of the BWRX-300 because the UK government has asked us to following GE-Hitachi’s application to DESNZ.

Step 1 is the preparatory part of the GDA process when we make agreements with the RP and provide advice on the scope and development of its submission. The length for Step 1 advised in our guidance is 12 months. It includes a review and confirmation that the RP has established adequate arrangements for GDA. Step 1 of the GDA of the BWRX-300 took 12 months, from early January 2024 to mid-December 2024.

At the start of Step 1, the Environment Agency entered into an agreement with GE-Hitachi under Section 37 of the Environment Act 1995 (EA95) to carry out work and recover our costs for a 2-step GDA of the BWRX-300. NRW entered into an agreement with GE-Hitachi under the Natural Resources Body for Wales (Establishment) Order 2012. We began the GDA of the BWRX-300 after signing these agreements in January 2024.

We set out, jointly with ONR, a timetable for Step 1 of the GDA process in response to GE-Hitachi’s proposed GDA programme. In addition to providing feedback and advice on the contents of the GDA scope and submissions, we agreed detailed working arrangements with GE-Hitachi covering matters such as:

• producing and controlling documents
• how GE-Hitachi will document its environment case and submit it for assessment during the GDA process
• how GE-Hitachi will address any gaps in meeting our regulatory requirements, the gaps it has identified, and its plan for the work to address the identified gaps
• the arrangements GE-Hitachi has put in place to carry out the GDA and tracking of commitments within and beyond GDA
• the schedule and associated programme for the subsequent step
• the arrangements for initiating and managing the Step 2 public comments process

As we approached the end of Step 1, we carried out a regulatory readiness review which confirmed that GE-Hitachi has met the requirements needed to complete Step 1. We and GE-Hitachi have resources in place to begin work on Step 2 (Fundamental Assessment). Our review considered the readiness review GE-Hitachi carried out on its own readiness for Step 2. This is considered in the detail of Step 1 activities in this report.

We have now completed Step 1 of the GDA process. We outline our Step 1 activities and give our conclusions in this report.

Next steps

Our next step is to begin Step 2 (Fundamental Assessment). We expect to begin Step 2 of the BWRX-300 GDA in December 2024.

At the end of Step 2, we will publish a GDA Step 2 Statement setting out our regulatory position at this point, and a Fundamental Assessment Report detailing our findings from the Fundamental Assessment.

GE-Hitachi currently plans to stop GDA at the end of Step 2.

Details of Initiation (Step 1) activities

This section summarises the outcome of the GDA Step 1 (Initiation) activities.

Objectives

The objectives for Step 1, as stated in our GDA guidance for Requesting Parties, are for the RP and the Environment Agency to agree:

• the scope of the GDA
• how the RP will document its environment case and submit it for assessment during the GDA process
• how the RP will address any gaps in meeting regulatory requirements; the expectation is that where it has identified gaps, it has a plan to complete this work
• the arrangements the RP has put in place to carry out the GDA
• the schedule and associated programme for subsequent steps, including plans for submissions
• the development of the RP’s website and comments process ready for entry to Step 2

During Step 1, with ONR, we carried out a joint assessment of GE-Hitachi’s GDA project management arrangements to give us confidence in the quality of the GDA submissions we receive.

We provided feedback and advice to GE-Hitachi on the documents submitted during Step 1, including the GDA scope, the proposed schedule of submissions, the structure of the submissions, and our expectations of the contents of the parts of the submissions relevant to the environment case.

Interface arrangements

One of the first activities in GDA Step 1 is for the RP and the regulators to agree and implement the interface arrangements to be used throughout GDA. This includes meeting arrangements; ensuring there is full access to any relevant commercially confidential information, including any which is the property of third parties; and obtaining all the necessary export licences to enable the transfer of information to and from the UK for all relevant countries.

The interface arrangements to be used throughout GDA were agreed by GE-Hitachi, ONR, the Environment Agency and NRW^{[footnote 1]}. The interface arrangements ensure that all interactions, communications and information exchanges between the regulators and GE-Hitachi, which are required as part of GDA, are properly defined and managed.

In all GDAs, the regulators review and assess submissions from the RP, using an agreed approach of 3 tiers of regulatory questions:

• Regulatory Query (RQ) – this is a request by the regulators for clarification and additional information – it does not necessarily indicate a perceived regulatory shortfall in the design or its substantiation
• Regulatory Observation (RO) – this is raised when the regulators identify a potential regulatory shortfall in the design or its substantiation – for a 2 Step GDA, the RP must have a resolution plan in place to be able to complete Step 2
• Regulatory Issue (RI) – this is raised when the regulators identify a serious regulatory shortfall in the design or its substantiation which could prevent them from issuing a SoDA (or a Design Acceptance Confirmation (DAC) from ONR) – the RP must take action to resolve it

The interface arrangements define the approach to responding to regulatory questions.

In response to setting up our JPO and agreeing the interface arrangements, GE-Hitachi has developed its own Regulatory Interface Office (RIO) and associated work instruction to ensure the Interface arrangements are adopted by the RP and its supporting UK contractors, Amentum.

Scope of the BWRX-300 GDA

Our GDA guidance expects the RP to provide a scope of GDA with enough information and sufficient functional specifications for the design, so that we can carry out a meaningful GDA. The scope of the environment case should include all relevant topics and sufficient details about the nuclear power plant design. The scope should be clear about whether the GDA will be a 2 or 3 step assessment, and whether the RP is aiming for a SoDA to be issued. We accept that full engineering details may not be available at the GDA stage, as some may only be finalised once the site-specific requirements are known and during the procurement and construction programme.

Where there is not enough information on a particular topic, we may agree to exclude that topic from the GDA scope, provided that the GDA remains meaningful, and the topic can be addressed effectively at a later stage. This could be during the application for site-specific environmental permits and during detailed design and procurement stages.

GE-Hitachi provided a scope document in May 2024^{[footnote 2]} and, following regulatory review and discussion, it issued Revision 1 in August 2024^{[footnote 3]} and Revision 2 in September 2024^{[footnote 4]}. The scope details the:

• applicable structures, systems and components (SSCs) of the reactor design
• the level of design maturity
• applicable life cycle stages and operating modes
• relationship with the GDA topic activities, which defines the scope of the submissions

The scope indicates that GE-Hitachi is intending to progress to the end of GDA Step 2 and the GDA will be carried out on a single reactor unit.

The scope document is aligned with a design reference report (DRR)^{[footnote 5]}, which defines the design reference point (DRP) to be assessed in GDA. The document identifies the standard design documents supporting the design reference (DR) and the design change control process, used to track changes to the design as the reactor progresses to a site-specific deployment.

We also reviewed the environmental strategy^{[footnote 6]}, which defines the structure and content of the environmental case, based on the proposed scope and design reference. Since this was reviewed, both the scope document and DRR have been revised, but the structure and content of the preliminary environmental report (PER) remain applicable.

We are content that the scope^{[footnote 4]}, design reference report^{[footnote 5]}, environmental strategy^{[footnote 6]} and the documents itemised in the Master Document Submission list (MDSL) define the scope of the GDA and are likely to achieve a meaningful Step 2 GDA.

Sustainability

There is an expectation for the RP to consider sustainability in the design, and this will be included as a cross-cutting engagement topic within our assessment. Sustainability is a topic of interest to the Environment Agency and NRW as highlighted in our GDA guidance for Requesting Parties and through our duties set out in the Environment Act 1995 (EA95) and the goals and principles of the Well-being of Future Generations (Wales) Act 2015 and Part 1 of the Environment (Wales) Act 2016, respectively.

GE-Hitachi has recognised the importance of sustainable development and has been keen to engage on the topic of sustainability in Step 1. However, there will be no separate sustainability focused submission, but the sustainability aspects will be embedded throughout the PER. We and NRW recognise GE-Hitachi’s willingness to explore this topic at a time when significant positive impacts could be realised from decisions made during the detailed design process.

GDA schedule

GDA of the BWRX-300 was originally planned to last 22 months. Step 1 (Initiation) started in January 2024 and finished in mid-December 2024, 6 weeks later than originally scheduled.

Step 2 (Fundamental Assessment) will start in December 2024. The current proposed Step 2 end date is December 2025, but this may be subject to future review.

Gap analysis

Our GDA Guidance for Requesting Parties requires the RP to identify any gaps or shortfalls in its design and environment case with respect to the information that we are expecting it to provide. We will provide advice to the RP to help identify such gaps or shortfalls. The RP must agree with us how it proposes to resolve these gaps and meet our regulatory requirements and expectations.

The regulators raised RQ-01448 to determine the scope and arrangements for the gap analysis and how any identified gaps would be captured and closed out.

The scope of the gap analysis looked at the suite of US and Canadian licensing documents and their primary references and overarching strategy and specifications. These were reviewed for any gaps against UK relevant good practice (RGP) for the format and content of the proposed Step 2 submissions.

Identified gaps were then agreed and scoped through a Gap Analysis Review Panel held by GE-Hitachi to determine whether further work should be performed and when this would be most appropriate and recorded as a forward action plan (FAP). This follows the process provided in the forward action plan report^{[footnote 7]}.

Gaps relevant to the UK environmental regulations to be closed during GDA Step 2 were identified around the demonstration of optimisation (that is both as low as reasonably practicable (ALARP) and best available techniques (BAT)) and the need for an approach to identify and assign environmental protection functions (EPFs) to structures, systems and components (SSCs).

Assessment of GE-Hitachi’s arrangements for carrying out the GDA

Our GDA guidance for Requesting Parties states that during Step 1 of GDA the RP should set up project management and technical teams; arrangements for carrying out a GDA; arrangements for preparing and submitting documents during Step 1; and arrangements for Step 2 of GDA.

During Step 1, we and ONR jointly assessed the management arrangements that GE-Hitachi will use to carry out a GDA to give us confidence in the quality of the submissions we receive. We carried out a relatively detailed assessment of the management arrangements, including quality assurance during Step 1 of the GDA to give us early confidence that:

• the design will be developed, and the submission produced, by suitably qualified and experienced people, including staff and contractors
• there will be an appropriate level of verification, review and approval of design and submission documents, including those produced by contractors, and the submission will accurately reflect the design
• the design will be developed, taking environmental requirements for all plant life cycle stages into account
• design changes will be controlled, evaluated for their impact on the environment, recorded and reflected in the submission

GE-Hitachi’s GDA management arrangements are summarised in the project implementation plan (PIP)^{[footnote 8]} and the project execution plan (PEP)^{[footnote 9]}. The PIP describes the GE-Hitachi project management and quality arrangements for the regulatory assessment of the BWRX-300 standard design during Steps 1 and 2 of the GDA. It also describes the arrangements between GE-Hitachi and its technical support contractor (TSC) that are contracted by GE-Hitachi to support it through the Step 1 and 2 GDA assessment. The PEP provides details of GE-Hitachi’s programme governance and project controls, including project metrics and performance indicators and the management of project and technical risks.

We carried out our assessment during Step 1 via desktop reviews of submissions and a face-to-face meeting to evaluate GE-Hitachi and its TSC (Amentum) arrangements. Our guidance identifies 9 topic areas that should be covered by GE-Hitachi’s management arrangements; our assessment of these areas for Step 1 is outlined below.

Developing the design

The BWRX-300 design is being developed in the US by GE-Hitachi. As part of a GDA, the RP is required to provide a design reference point (DRP) which defines the design that is to be assessed during the GDA. As the design of the BWRX-300 is still under development, the DRP in this case is a snapshot of the current stage of the design, noting that different parts of the proposed plant will have different levels of design maturity. The regulators’ guidance also requires information on the design reference (DR) to be provided. This lists all the documents that comprise the design of the nuclear power plant that are applicable to the generic design assessment (GDA) submissions provided to the regulators. This is usually provided during Step 2 of a GDA, and it forms the basis of our assessment in Step 2 and 3. However, as GE-Hitachi does not intend to amend the design being assessed during this GDA and intends to exit the process at the conclusion of Step 2, it has stated that for this GDA the DRP and DR are the same. GE-Hitachi has provided information to us on the DRP and DR and its position regarding them in document^{[footnote 5]}.

We do not have any concerns about the arrangements that we have assessed so far to implement the BWRX-300 design. Further work will be required in Step 2 for us to confirm the described arrangements are being worked to and to review the work that GE-Hitachi intends to carry out to assess the design against UK regulatory requirements.

Managing the GDA project

GE-Hitachi has adopted conventional project management arrangements, including setting project objectives, having quality assurance procedures, managing a schedule, and monitoring performance using metrics, with these being outlined in the PIP and PEP documents. Our engagement during Step 1 concludes that GE-Hitachi’s project management arrangements are adequate, and we have not identified any significant concerns with their implementation.

Managing and controlling contractors and others involved in GDA

The RP’s staff includes GE-Hitachi employees and embedded contractors from Amentum (who are also acting as a TSC to the project). The arrangements that GE-Hitachi has put in place to manage these resources are described in Section 3 of the PIP document.

Both GE-Hitachi and Amentum staff are required to complete appropriate training and competency assessments, and to ensure they are suitable to carry out their roles. During our evaluation, both GE-Hitachi and Amentum provided information on how competence management is managed in their respective organisations. Both companies also provided evidence of the records that are generated from these processes.

GE-Hitachi provided evidence of resource planning in response to RQ-01506, an RQ raised by the regulators to request a range of evidence relating to management for safety and quality assurance (MSQA). The response was in the form of a table of estimated hours per topic (for example, BAT, discharges, monitoring) created at the start of the GDA. GE-Hitachi provided evidence of a weekly GE-Hitachi project resource meeting, which reviews resource allocations and needs for all its licensing projects globally.

In our evaluation, we viewed a matrix which identifies which GE-Hitachi and Amentum staff lead and advise respectively on different parts (for example, technical areas) of the project. A Responsible, Accountable, Consulted and Informed (RACI) matrix is provided in Table 18-1 of the PIP, which sets out these arrangements for the GDA project. GE-Hitachi is clear that it acts as the ultimate ‘Intelligent Customer’ for accepting work from its contractors, with appropriately qualified and experienced GE-Hitachi staff signing off such work.

GE-Hitachi also provided details of its surveillance schedule for GE-Hitachi Advanced Nuclear Programs, its Amentum Suitably Qualified Experienced Personnel (SQEP) Surveillance Plan and the associated report for this surveillance audit. GE-Hitachi carried out the audit of Amentum’s SQEP arrangements for the project in July 2024. Both the plan and audit report appeared to be of an acceptable standard. GE-Hitachi also provided its Training Proficiency Surveillance Plan, which Amentum carried out in August 2024. We may assess the outputs of similar audit activities by GE-Hitachi as part of our Step 2 assessment.

Overall, we judge that GE-Hitachi appears to have suitable procedures in place to scope, manage and evaluate the work of staff and contractors for Step 2 of the GDA.

Establishing the methodology used to identify best available techniques and making sure it is used in the design

The section ‘Radioactive waste management arrangements (RWMA), including best available techniques’ of this document provides an overview of GE-Hitachi’s plans with respect to a methodology for identifying BAT. In summary, we met GE-Hitachi to discuss its approach, and a description of the BAT methodology will be provided in Chapter 6 of the PER document as part of our Step 2 assessment.

Producing and maintaining the GDA submission

GE-Hitachi summarises the processes and responsibilities for producing and maintaining the total GDA submission in section 5.2 of the PIP document. During the MSQA intervention, we viewed evidence of these processes being used, with documents produced by Amentum and reviewed and accepted by GE-Hitachi.

GE-Hitachi has supplied a description of its quality management arrangements in GE-Hitachi Nuclear Energy, Quality Assurance Program Description^{[footnote 10]}. This programme meets the requirements of the American Society of Mechanical Engineers’ (ASME) Nuclear Quality Assurance (NQA-1) and has been endorsed by the US NRC, most recently in October 2022. GE-Hitachi also holds relevant international accreditations, such as ISO 9001:2015 for quality assurance management (a copy of GE-Hitachi’s most recent certificate was provided) and ISO14001:2015 for environmental management (according to the GE Vernova Sustainability Report 2023).

GE-Hitachi has provided information on the proposed structure of the preliminary environmental report in its environmental strategy document^{[footnote 6]}, with GE-Hitachi noting that there are close links between it and the preliminary safety report (PSR). The processes for the development, issuing and updating of documents submitted to the regulators will be controlled using GE-Hitachi’s procedure CP-25-300^{[footnote 11]}, along with its supporting procedures, guidance and forms.

The RP has provided both a MDSL and a Document List (DL). The MDSL is the list of the latest revision of each formal GDA submission, and the DL is the list of all information transmitted to the regulators. While the arrangements for using the MDSL and DL are adequately covered in the PIP document, there have been inconsistencies in its use in Step 1. The assessment of the implementation of these arrangements will be part of our Step 2 assessment.

The PER and the arrangements for its production, its future updating, and its technical content will be evaluated as part of our Step 2 assessment.

Ongoing communications with the regulators and matters raised by them during GDA

GE-Hitachi has agreed interface arrangements with the regulators and has a procedure (CP-25-300)^{[footnote 10]} that provides the requested information in response to RQs, ROs and RIs. Section 5 of the PIP document provides detail on the control of documents and interfaces for the project.

GE-Hitachi has responded to several RQs during Step 1, and Step 2 engagement plans are in the process of being agreed. We have not currently identified any concerns with GE-Hitachi’s communications with regulators, or with the company’s response to matters raised by regulators so far during this GDA. We will carry out further assessment work of this area in Step 2 of the GDA.

Maintaining records of design and construction

How potential changes to the design are controlled and how these are documented are set out in GE-Hitachi documents such as in the BWRX-300 Design Reference Report^{[footnote 5]} and the BWRX-300 Design Plan^{[footnote 12]}. As part of our GDA Step 1 assessment, we only looked to identify that GE-Hitachi has arrangements in place for maintaining records of design and construction, which it has. We will look more closely at these arrangements and their outputs as part of our Step 2 assessment.

Controlling and documenting design modifications, both during and after completion of GDA

GE-Hitachi states in section 11 of the PIP that it does not anticipate design changes to the DRP and DR during the GDA assessment of the BWRX-300. However, GE-Hitachi recognises that there is a need to have arrangements to formally address and implement design changes during the GDA should these prove necessary. GE-Hitachi states within the PIP that design changes identified during the GDA process will be formally addressed and implemented via a FAP, with these being addressed in the later site-specific phases of the project. The PIP provides an outline of how a FAP is managed, and signposts to GE-Hitachi procedure Product Lifecycle Management Issue Management CP-03-100-G515^{[footnote 13]} under the GE-Hitachi CP-03-100 Design Control Governance process^{[footnote 14]}. These arrangements have not yet been examined but will form part of our assessment in Step 2.

The GE-Hitachi BWRX-300 UK GDA Design Reference Report^{[footnote 5]}, as well as providing information on the DRP and DR, also provides an outline of GE-Hitachi’s design responsibilities and control processes used to develop and maintain configuration control of the design and the arrangements for managing any commitments (such as via FAPs) made regarding changes to the design that are agreed to be deferred to beyond GDA Stage 2.

Transferring information to prospective operators and providing ongoing support to them throughout the nuclear power plant reactor’s life cycle

Arrangements for providing information to prospective operators has not yet been assessed; this will be evaluated in Step 2 of our assessment.

The environment case

Our guidance expects the RP for GDA to agree with us the scope, structure and format of its environment case submission.

Full engineering details of the reactor may not be available at the GDA stage. It is normal to finalise engineering details once the site-specific requirements are known and during the procurement and construction programme. However, the RP is expected to provide enough functional specifications for its design so that a meaningful GDA can be carried out.

A sufficiently detailed environment case needs to be developed. Our guidance expects the RP to provide relevant plant and process descriptions, including engineering drawings, process flow diagrams and other information that will help us understand the nuclear power plant design, its underpinning design philosophy, and its environmental protection features.

The RP’s response to these expectations is addressed in its environmental strategy document^{[footnote 6]}, which provides the structure of the environmental case and the design reference report^{[footnote 5]}, which provides the underpinning design information.

Environment case structure

The environmental strategy document sets out that there will be a header document describing the integrated safety, security, safeguards and environment (SSSE) case.

Beneath the header document there will be the 4 main SSSE case documents:

• preliminary safety report (PSR)
• preliminary environmental report (PER)
• generic security report (GSR)
• preliminary safeguards report (PSgR)

The PER will consist of 10 chapters:

1. Introduction
2. Generic site description
3. Management arrangements and responsibilities
4. Information about the design
5. Radioactive waste management arrangements
6. Demonstration of BAT approach
7. Radioactive discharges
8. Approach to sampling and monitoring
9. Prospective radiological assessment
10. Other environmental regulations

The PER will be supported by an integrated waste strategy (IWS), a demonstration of disposability, an expert view from Nuclear Waste Services (NWS), and a document that will map the alignment of the submission with our RSR objective and principles and the generic developed principles. There will also be system description documents made available for the systems important to management and disposal of radioactive waste.

During Step 1, we provided advice to GE-Hitachi on our expectations for the environment case in readiness for Step 2. Our technical assessment will begin in Step 2.

Radioactive waste management arrangements (RWMA), including best available techniques (BAT)

During GDA, the RP must provide information on the strategic considerations for radioactive waste management which underpin the design. It must also provide a description of all radioactive waste and spent fuel arisings throughout the lifetime of the plant, and proposals for the management and disposal of these wastes and spent fuel, in a way that protects people and the environment.

During GDA, the RP must also provide its approach for determining BAT to prevent or minimise the generation of radioactive waste and its environmental impact during the lifetime of the plant, including design, construction, commissioning, operation and decommissioning.

GE-Hitachi provided a scope document in May 2024^{[footnote 2]}. We reviewed the scope and provided feedback to GE-Hitachi on our expectations for the RWMA assessment topic during Step 2. This feedback was provided during several interactions with the RP during Step 1, through both the BAT assessment topic meetings and the joint ONR Nuclear Liabilities and Environment Agency Radioactive Waste meeting.

In relation to strategic considerations, the IWS will form the basis of our assessment during Step 2. We will also refer to several chapters of the PER and PSR to support our assessment, as well as relevant design information. We may choose to request additional references from within these documents via the RQ process or through routine interactions with the RP.

In relation to BAT, Chapter 6 of the PER, Demonstration of BAT approach, will form the basis of our assessment during Step 2. We expect Chapter 6 to provide us with:

• a description of the BAT methodology and decision tool
• BAT claims and arguments (including reference to relevant evidence)
• a worked example
• a forward action plan to address any identified gaps

We will also refer to several chapters of the PER and PSR to support our assessment of BAT, as well as the IWS and relevant design information. We anticipate several submissions relevant to the MSQA assessment topic may also be relevant to our assessment, such as management arrangements relating to design change and decision-making.

Discharges

Our GDA guidance expects the RP to present information on the quantities and types of radioactive waste (gaseous, liquid and solid) and spent fuel that are likely to arise from the reactor design.

Assessment of this topic area, like other environmental topics, depends on a detailed source term being provided to demonstrate the minimisation of waste arisings and the calculation of discharges and limits.

GE-Hitachi provided a scope document in May 2024^{[footnote 2]}. We reviewed the scope and provided feedback to GE-Hitachi on our expectations and some concerns around proposed scope exclusions for headroom factors and discharge limits. The scope document has since been updated to Revision 2 in September 2024^{[footnote 4]}.

Through technical discussions, it was established that the RP intended to derive discharge estimates based on the primary coolant source term from the American National Standards Institute (ANSI 18.1 2020) and use of the US NRC developed model for discharges, GALE 3.2 (NUREG-0016 Revision 2). The ANSI source term is based on plant data and, as such, is likely to contain the transients of normal operations known as ‘anticipated operational occurrences’ or ‘expected events’. The data is also based on a time when fuel failure was higher than expected for modern plants. The GALE 3.2 code is also very conservative, incorporating additional expected events and assumes low efficiency abatements. On this basis, the estimated discharges are likely to be significantly overestimated, representing a bounding case.

Our guidance asks the RP to estimate discharges and then add on a headroom factor to allow for uncertainty and expected events to define proposed discharge limits. As these are already incorporated into the data and models the RP proposes to use, we agreed that to add further factors could result in overly conservative estimates and be inappropriate. However, we will expect a clear narrative from the RP in its Step 2 submission as to why this approach is appropriate and justified, in addition to an understanding of how discharge estimates will be refined in future project phases.

Therefore, the discharge estimates we will be presented with will also be the proposed limits.

The basis of assessment will be the PER Ch 7 Radioactive Discharges, with supporting information provided from main references (such as ANSI 18.1 2020 and GALE 3.2 Revision 2), PSR Ch 23 Chemistry and other PSR chapters relating to the description of the design.

Solid waste, spent fuel and disposability

During GDA, the RP must provide information on the quantity and disposability of any solid radioactive waste arisings. This is a topic area where we work closely with ONR, as we are looking at the same wastes but through the lens of different legislation. We will work together to ensure that we do not give conflicting advice to the RP.

During GDA, the RP must provide information on the strategic considerations for radioactive waste management which underpin the design. It must also provide a description of all radioactive wastes and spent fuel arising throughout the nuclear power plant’s life cycle, and the proposals for its management and disposal.

GE-Hitachi provided a scope document in May 2024^{[footnote 2]}. We reviewed the scope and provided feedback to GE-Hitachi on our expectations. The scope document was subsequently updated to Revision 1 in August 2024^{[footnote 3]} and Revision 2 in September 2024^{[footnote 4]}.

Our guidance for RPs outlines our expectations for information to be submitted for a Step 2 GDA, and overall, the RP has most of this in scope for this GDA. For example, the scope includes identifying all waste types and quantities, albeit at a high level in some cases and producing an IWS. An expert view from NWS for the disposal of wastes to a geological disposal facility will be sought by the RP and provided as part of GDA. Documents will also be produced to cover radioactive waste management, fuel and core, spent fuel management and decommissioning. Although these documents will sit within the PSR, they will also be assessed by the Environment Agency to determine how the disposal of wastes generated by these activities are described.

The potential limitations to our assessment that have been identified for a Step 2 GDA are the exclusion of the interim storage facilities for wet solid ILW, the exclusion of the management of failed fuel, and the high-level coverage only of LLW and decommissioning wastes.

The interim storage facilities for wet solid ILW are expected to carry out critical activities (treatment, conditioning etc.) that may affect the disposability of these wastes. Secondary radioactive wastes are also likely to be generated as the result of any storage and management activities that take place before ultimate disposal. These aspects will not be able to be assessed as part of this Step 2 GDA as they are reliant on decisions to be made by a future operator. Similarly, how failed fuel is managed may affect its disposability and could result in secondary waste generation.

Over the life cycle of the facility (construction, commissioning, operation and decommissioning), LLW is likely to be a much larger volume waste stream than ILW and high level waste (HLW), with more possible disposal routes available to it, only one of which is disposal to the LLWR. This will mean the waste hierarchy will need to be considered, therefore introducing an additional layer of decision-making to ensure that all wastes go down optimised disposal routes. Similarly, in addition to operational wastes of all categories, the whole facility will need to be disposed of at some point in the future, and much of this could be covered in some detail at GDA (in other words, everything that is built will need to be disposed of). The scope document does acknowledge that LLW and decommissioning wastes will be included in this GDA but only at a high level. Our assessment can only be as detailed as the information provided allows.

Anything that is excluded from the scope of GDA carries risk going forward, as it will have to be addressed before an environmental permit can be issued at a specific site. The FAP for work that will need to be carried out by a future operator after this Step 2 GDA will, therefore, form a critical part of this assessment.

Sampling and monitoring

RPs must provide appropriate information on sampling arrangements, techniques and systems for measuring and assessing discharges and disposals of radioactive waste. These must cover in-process monitoring and the monitoring of final discharges and disposals.

GE-Hitachi provided a scope document in May 2024^{[footnote 2]}. We reviewed the scope and provided feedback to GE-Hitachi on our expectations for the sampling and monitoring topic during Step 2. The latest version of the scope document was received in September 2024^{[footnote 4]}.

The scope includes identifying all proposed authorised gaseous and liquid discharges under normal conditions. There will be descriptions of the design and arrangements for how discharges to the environment are to be monitored or measured and sampled. This includes identifying the arrangements for where and how the RP will make provision for any independent monitoring, measurement, sampling and the plant design and arrangements for any leak monitoring, measurement, sampling systems. The RP will provide a description of the BWRX-300 system design for the Process Radiation and Environmental Monitoring System (PREMS) and arrangements for characterisation of wet solid and dry solid radioactive wastes. The claims and arguments that will be used in later submissions to demonstrate that BAT is being used, will also be given.

Our assessment will consider whether it has been demonstrated that the needs and requirements for sampling and monitoring are understood, and options for a future operator are not being foreclosed (for example, plant being designed to accommodate required infrastructure such as platforms, sampling lines, ports and access. We will look at the process for how options for sampling and monitoring are being generated and considered and the processes for taking important decisions on sampling and monitoring.

The PER Chapter 8: Approach to Sampling and Monitoring will form the basis of our assessment. Additionally, Chapter 5: Radioactive Waste Management Arrangements will be considered for a description of solid waste management systems and Chapter 7: Radioactive Discharges will be considered for a description of gaseous and liquid waste management systems.

The potential for this design to be operated as a zero liquid discharge plant, or if discharges do occur, being infrequent and low volume, will need to be considered in the approach taken to monitor liquid discharges.

Generic site and radiological impact assessment

During GDA, the RP must provide information on the likely impact on people and the environment from any proposed discharges of gaseous and liquid radioactive waste.

We expect a description of the type of site where the power plant could be built (the generic site). This description should include the environmental characteristics and constraints. The generic site description will shape the input to the assessment of the radiological impact on people and the environment. The RP is required to describe one or more generic sites and make dose and other assessments against these site descriptions.

GE-Hitachi provided a scope document in May 2024^{[footnote 2]}. Following technical discussions with the RP, the scope document has since been revised^{[footnote 3]} and ^{[footnote 4]}. GE-Hitachi has indicated that it will consider a single unit operating on a generic UK coastal site using a once-through cooling system with seawater as the ultimate heat sink. The generic site should be appropriate for assessment of the radiological impact on members of the public and the environment and should identify any siting constraints. In relation to the generic site, Chapter 2 of the PER: Generic Site Description will form the basis of our assessment during Step 2.

In relation to radiological impact, PER Chapter 9: Prospective Radiological Assessment will form the basis of our assessment during Step 2 of GDA. We expect the RP to provide an assessment of the expected impact on humans and non-human species from the proposed discharges of aqueous and gaseous radioactive wastes to the environment, which reflects the generic site. This assessment should use an appropriate approach and tool to demonstrate that radioactive discharges from the reactor design would be within with UK dose constraints and limits.

GE-Hitachi has stated that it will provide a prospective radiological analysis for members of the public and non-human species using the Environment Agency’s Initial Radiological Assessment Tool (IRAT). We will assess the method used to calculate doses and the justifications as to why the model’s input data and assumptions used are appropriate. GE-Hitachi has expressed within the scope document that the radiological assessment will include the derivation of the direct radiation dose component using appropriate BWR operational experience and that mathematical modelling of direct dose for radiological impact assessment is out of scope. In addition, the potential short-term dose, accumulation of radionuclides in the local environment, collective dose and annual dose to representative person for the facility, are all out of scope. This is consistent with our expectations for Step 2 of GDA as these require detailed modelling. However, these assessments would be required for a GDA Step 3 detailed assessment and for application of an environmental permit.

We will refer to other chapters of the PER, including Chapter 7: Radioactive Discharges to support our assessment. We may also choose to request additional references from within these documents via the RQ process or through routine interactions with the RP.

Other environmental regulations

In our guidance, the RP is expected to provide information explaining how it will meet other relevant environmental regulations. This includes potential impacts on people and the environment of discharges from back-up diesel generators, cooling and process water discharges, other waste management activities/disposals, and information about its approach to applying BAT (where applicable).

Through our discussions in technical meetings, we have been able to provide clarity to the RP on our expectations, and we have discussed each section of the guidance to understand the proposed scope of the submissions we will receive in Step 2 and what may be left as a forward action.

We expect Chapter 10 of the PER to provide the basis for our assessment in Step 2. We expect this chapter to provide us with estimates of cooling water and mains water abstraction volumes based on pump rates and basic operating modes, discharge quality and volume estimates across numerous effluent streams, combustion activities, Control of Major Accident Hazards (COMAH) implications and fluorinated gases and ozone depleting substances (ODS) details.

The reactor vessel is sited mainly below ground in an engineered containment structure. Therefore, we have also asked for information to be provided on how the design provides protection from and management of ground water ingress, and any associated contamination throughout the lifetime of the plant.

Standards and guidance

The RP is expected to show how it will take account of Environment Agency guidance, in particular our Radioactive substances regulation (RSR) objective and principles and the RSR generic developed principles for regulatory assessment.

It has been agreed that GE-Hitachi will produce a supporting document to address this expectation.

Document submission schedule

The RP has provided a schedule for submitting the environment case. GE-Hitachi intends to submit the safety, security, safeguards and environment (SSSE) case at the end of Step 1, in readiness for Step 2 assessment.

Towards the end of the Step 2 assessment window, and before regulators write up their findings, GE-Hitachi will submit a revised SSSE case. This will consolidate any changes needed as a result of regulatory assessment or other project changes. For example, additional information from RQs, ROs, RIs or updated supporting information.

The SSSE case will be produced as a portable document format (PDF).

Website and public comments process

To progress to Step 2, the RP must put processes in place so that the public can interact with the GDA throughout Step 2. The RP should provide information on a public website about the proposed design and how it will meet standards for environmental protection, safety, security and safeguards. The website should enable the public to see the information the RP has provided to the regulators as part of GDA, make comments and ask questions.

The RP must agree with the regulators the information that it will publish on its website. It will be expected to update this public information whenever it makes any significant changes to the information it submits to the regulators. The RP must also agree with the regulators the process and timescales it will use to respond to comments from the public. It must provide the comments and questions raised by the public to the regulators, as well as its responses.

GE-Hitachi has developed a GDA website and agreed to publish the SSSE documents at the start of Step 2. Each document has been written with publication in mind, however, some commercially confidential information may need to be removed. The decision- making on what needs to be redacted will be made by the RP Design Authority team and will be discussed with the regulators.

The website incorporates a public comments process. The RP has defined a work instruction for managing and responding to public comments; this was shared for information, but not formally submitted^{[footnote 15]}. The process includes a review panel to review and allocate the comment to the appropriate respondent and a tracking system. Comment responses must be made in a specified time. During Step 2, the RP also proposes to publish a summary of comments received and the responses.

The website and the comments process will go live at the start of Step 2 of GDA.

Readiness review

Our GDA guidance for Requesting Parties requires that we should not progress to Step 2 until we and the RP are ready. To demonstrate readiness, both we and the RP carried out a review of readiness to move to Step 2.

GE-Hitachi’s readiness review

GE-Hitachi carried out a readiness review to demonstrate its readiness to progress to Step 2 of GDA^{[footnote 16]}. This documents the process followed, a summary of the evidence considered, and its conclusions on readiness for Step 2. Its process included an independent review by GE-Hitachi staff who were not part of the GDA team, with a final decision made by its GDA project board.

The RP compared the requirements from the regulators’ guidance with documents submitted, including providing the scope and schedule. It demonstrated that it had carried out a gap analysis, had identified gaps between existing documentation and UK regulatory requirements, and had work plans in place to close those identified gaps needed for GDA. It also had tracked plans in place to track other gaps through the later stages of the project. The RP looked at how well communications between itself and the regulators were working and identified improvements. It also documented its approach to ensuring enough resource was available for Step 2. All this evidence was reviewed by a RP representative who was independent of the GDA project.

The RP identified some risks and improvements for Step 2.

1. It had been too focused on deliverables and not organisational maturity and performance, and a better balance needs to be found.
2. There are competing demands for resources from the other BWRX-300 projects globally. This risk is being managed using their UK technical support contractors (TSCs), Amentum and others.
3. Project structure and accountabilities could be improved.
4. Some risks lie outside the GDA project, and although concerns were escalated to the GDA project board, action was not taken to resolve the issues.

From the readiness review, 21 actions for improvement were identified. The independent reviewer identified 5 recommendations, which included closing the actions for improvement, a final review before moving to Step 2, more clarity on escalation and oversight arrangements, improved management of schedule changes, and continuing independent reviews.

Following the RP’s self-assessment readiness review, the RP’s GDA project board has declared that it is ready to enter Step 2, subject to the completion of the 21 actions identified.

Our readiness review

We reviewed the progress of GE-Hitachi in Step 1 against the requirements in our GDA guidance for Requesting Parties and the more general project-focused requirements in Appendix 2 and Appendix 3 in the ONR GDA guidance to Requesting Parties. Progress against many of the important aspects are discussed above as Step 1 activities.

We are content that GE-Hitachi has completed the requirements for Step 1.

As part of our engagement in Step 1, we have reviewed the Step 2 submission schedule GE-Hitachi provided. The original Step 1 end date has been delayed by 6 weeks. As a result, the target end date for Step 2 is now December 2025.

We have developed an assessment plan based on the Step 2 submission schedule. Through Step 1 engagements with GE-Hitachi, we are satisfied that there is likely be enough content in the submissions for us to assess during Step 2.

We have considered whether we have enough resources to carry out the assessment during Step 2 and suitable guidance to support the assessment process. We are content that we have sufficient resource allocated to complete Step 2.

We have joint regulator GDA webpages, hosted by ONR. The environment agencies also publish reports and GDA information on their own websites. The webpages are one of several communication channels used by the regulators to share information with the public.

Our readiness to proceed into Step 2 was agreed by our New Reactors Programme Board on 13 November 2024.

Conclusions from Step 1 (Initiation) assessment

GE-Hitachi is intending to progress to the end of GDA Step 2 (Fundamental Assessment), seeking a Step 2 Statement. This means that a SoDA will not be issued at the end of the GDA, and further detailed design assessment work will need to take place before any future site-specific regulation phase.

Interface agreements are in place which set out how GE-Hitachi will submit information and how we will track it, arrangements for correspondence and meetings, and how regulatory questions (RQs, ROs, and RIs) will be raised and tracked.

We have agreed with GE-Hitachi how it will publish the GDA information, how it will manage public comments, and when it will place documents on its website. GE-Hitachi currently plans to issue and publish all the GDA submissions relevant to the environment for the start of Step 2 of GDA.

We carried out an assessment of GE-Hitachi’s management arrangements for GDA jointly with ONR. Overall, based on our discussions and assessment, we consider that GE-Hitachi’s management arrangements are satisfactory for this stage of the GDA process. We have used our Step 1 assessment and review of our findings to develop an appropriate assessment plan for management arrangements in Step 2 of GDA. This includes an assessment of GE-Hitachi’s implementation of the arrangements we considered as being adequate in Step 1.

GE-Hitachi carried out a readiness review for its entry into Step 2 of GDA. It declared that it is ready to enter Step 2 of GDA and identified actions and risks and mitigation.

The environment agencies have carried out a review of GE-Hitachi’s progress in Step 1 and its readiness review. We have determined that the arrangements and resources GE-Hitachi has put in place to carry out the GDA are adequate to progress to Step 2.

We have agreed a GDA scope and a schedule for submitting the environment case information during Step 2.

The documentation GE-Hitachi provided addresses our information requirements for Step 1 of GDA as set out in our GDA guidance for Requesting Parties and the generic project requirements detailed in ONR GDA guidance to Requesting Parties.

We have concluded that we can progress to Step 2 of GDA.

Our next steps will be to finalise our detailed schedule for Step 2 and to begin to review and assess the submissions that GE-Hitachi provides for Step 2.

References

1. GE-Hitachi Nuclear Energy, Generic Design Assessment Interface Arrangements with GE-Hitachi International, ONR-GDA-IN-002, Issue 1, October 2024. ↩

2. GE-Hitachi Nuclear Energy, BWRX-300 UK Generic Design Assessment Scope of Generic Design Assessment. NEDC-34148P, Revision 0, May 2024. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

3. GE-Hitachi Nuclear Energy, BWRX-300 UK Generic Design Assessment Scope of Generic Design Assessment. NEDC-34148P, Revision 1, August 2024. ↩ ↩² ↩³

4. GE-Hitachi Nuclear Energy, BWRX-300 UK Generic Design Assessment Scope of Generic Design Assessment. NEDC-34148P, Revision 2, September 2024. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

5. GE-Hitachi Nuclear Energy, BWRX-300 UK GDA Design Reference Report. NEDC-34154P Revision 2, October 2024. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

6. GE-Hitachi Nuclear Energy, BWRX-300 UK GDA Environmental Strategy. NEDC-34141P Revision 0, June 2024. ↩ ↩² ↩³ ↩⁴

7. GE-Hitachi Nuclear Energy, BWRX-300 UK GDA Forward Action Plan. NEDC-34274P Revision 0, October 2024. ↩

8. GE-Hitachi Nuclear Energy, BWRX-300 UK Generic Design Assessment Project Implementation Plan, NEDC-34150P, Revision 0, September 2024. ↩

9. GE-Hitachi Nuclear Energy, BWRX-300 Future Nuclear Enabling Fund Project Execution Plan, 008N3539, Revision 0, April 2024. ↩

10. GE-Hitachi Nuclear Energy, Quality Assurance Program Description, NEDO-11209-A, Revision 17 December 8, 2022. ↩ ↩²

11. GE-Hitachi Nuclear Energy, New Power Plants Licensing Basis Document Development and Control Process, CP-25-300, Revision 4.0, June 2024. ↩

12. GE-Hitachi Nuclear Energy, BWRX-300 Design Plan, 006N3139, Revision 5, February 2024. ↩

13. GE-Hitachi Nuclear Energy, Product Lifecycle Management Issue Management CP-03-100-G515. ↩

14. GE-Hitachi Nuclear Energy, Design Control Governance process CP-03-100. ↩

15. GE-Hitachi Nuclear Energy, BWRX-300 UK Generic Design Assessment Regulatory Interface Office, WI WI-23-300-01. ↩

16. GE-Hitachi Nuclear Energy, BWRX-300 UK Generic Design Assessment (GDA) Step 2 Readiness Review. NEDC-34151P Revision 0, September 2024. ↩