Generic Design Assessment
GDA Process
The Environment Agency, Office for Nuclear Regulation (ONR) and Natural Resource Wales (NRW) have developed an assessment process called Generic Design Assessment (GDA). Regulators use the GDA to analyse new nuclear power plant designs and determine their acceptability for deployment in Great Britain.
The UK Government has awarded Holtec Britain £30 million of grant funding from the Future Nuclear Enabling Fund for Holtec to complete Steps 1 and 2 of the GDA to progress towards UK deployment of our Small Modular Reactor, SMR-300. Holtec is match funding the contribution from the Government.
The Environment Agency is working with the ONR and NRW to ensure that our Pressurised Water Reactor (PWR) meets the necessary high standards for:
- Environmental protection (including waste management)
- Safety
- Safeguards
- Security
Throughout the GDA process Holtec Britain are known as the Requesting Party (RP) and the Environment Agency, ONR and NRW are known as the Regulators.
The output from a GDA represents the regulators’ expert judgement that the proposed design of our reactor can safely be built, operated and decommissioned in Great Britain in line with the required safety, security, waste management, safeguarding and environmental standards.
Successful completion of the GDA does not guarantee the go ahead for the construction of a nuclear reactor. However, the regulators anticipate that future licensees are likely to want the design they are proposing to construct and operate to have undertaken a GDA, as this will demonstrate some regulatory certainty and thereby reduce the project risk.
Further key site-specific permissions from regulators and government need to be obtained before a new nuclear power station can be built. These include but are not limited to, a nuclear site licence and relevant consents from ONR, environmental permits from the Environment Agency or NRW and planning permission from the Planning Inspectorate.
GDA Documents
Holtec Britain will submit documents to the regulators during the GDA process. By undertaking the assessment process, Holtec have committed to share all major documents in the documents section of this website. Examples of these documents include (but aren’t limited to) the Preliminary Safety Report, Preliminary Environmental Report and the Generic Security Report.
Documents created by Holtec will be checked then submitted to the independent regulators to be assessed. All commercially or security sensitive information will be excluded, however we will strive to make as much information as possible available to the public.
In addition to the documents available on our website, the regulators will also publish information on their respective websites (see below). This information will clarify and support their evaluation.
Environment Agency – New nuclear power stations: assessing reactor designs
Technical Summary
| Parameter | Value |
|---|---|
| General Plant Data | |
| Reactor Type | Light Water Pressurised Water Reactor (PWR) |
| Reactor Core Size | 1,050 MWth |
| Design Life | 80 years |
| Major Planned Outages | Every 18 months (refuelling) |
| Lifetime Capacity Factor | >95% |
| Standard Plant Configuration | 2 units |
| Plant Design Data | |
| Capacity to Electric Grid (per unit) | 360 MWe (gross) 300 MWe (net, minimum) |
| Primary Coolant Circulation, Normal Operation | Pump Driven |
| Reactor Data | |
| Fuel Material | Uranium Dioxide |
| Plant Safety Characteristics | |
| Primary Coolant Circulation, Post-Accident | Gravity Driven |
| Passive Reactor Shutdown Methods | Yes |
|
Severe Accident Containment Provisions for Hydrogen Management | Yes |
Waste Management
How much waste management experience does Holtec have?
Holtec has provided safe, robust and reliable fuel and waste management solutions worldwide since 1986. 142 nuclear plants (including Pressurised Water Reactors) currently rely on Holtec for spent fuel storage and transport. This covers over 60% of the US Market and 40% of the international market.
Our HI-STORM UMAX waste storage planned for the SMR-300 is already fully functional across multiple reactors in the US, having been licensed by the US Nuclear Regulatory Commission in 2015. You can take a look at the patents granted for the technology here.
Does Holtec have waste management experience in the UK?
We worked with EDF Energy to implement an independent dry fuel store (DFS) facility at Sizewell B on the Suffolk coast to accommodate all spent fuel arising from the site until the end of its life.
The DFS uses Holtec’s double wall multi-purpose canisters (MPCs) and HI-STORM MIC casks. Each HI-STORM has a 100-year design life and multiple barriers against threats and accidents of all kinds.
Successful completion of the dry fuel store means Sizewell B can continue producing reliable low carbon power to supply 2.6 million British homes until at least 2035, and potentially for a further 20 years subject to life extension.
What kind of waste will be produced?
The SMR-300 will generate both radioactive and non-radioactive waste over its lifetime. None of the waste produced by SMR-300 will be the first of its kind – around three hundred Pressurised Water Reactors including Sizewell B are currently in operation and effectively managing similar waste worldwide.
Spent nuclear fuel is one form of radioactive waste that the reactor will generate. Used nuclear fuel is a solid material, in the form of ceramic pellets. Each pellet is just under 1cm in diameter and just over 1cm in length. The pellets are stacked inside long metal zirconium tubes approximately 3.7m long, which are sealed on each end to form a fuel rod.
The site will also generate solid, liquid, and gaseous waste, as well as other materials expected from any standard industrial site such as gloves and packaging.
While a certain level of waste is unavoidable for the safe operation of the plant, we prioritise minimising waste creation at the source. This will involve making sure that during the design process we prioritise minimising both conventional and radioactive waste generated by the construction, operation and decommissioning of the SMR-300.
Where does the nuclear waste go?
The SMR-300 has been designed to store the used fuel produced over the entire operating lifetime of the plant in on-site subterranean cavities in Holtec’s HI-STORM UMAX system.
Spent fuel from the entire 80-year design life of the SMR-300 can be stored in just 24 HI-STORM UMAX modules. For context, the image below depicts a real HI-STORM UMAX installation at a currently operating nuclear power plant. For 80 years of operation, a HI-STORM UMAX installation just half this size is required to safely store the SMR-300’s spent fuel onsite until final storage or reprocessing is required.
Safety
The SMR-300 has been designed to produce green electricity safely and securely in a way that protects people and the environment.
We have distilled principles into the design which have been derived from the basic safety functions identified in the International Atomic Energy Agency (IAEA’s) “Safety of Nuclear Power Plant Design”.
The reactor uses physical barriers and “walk away safe” features driven by natural forces (e.g., gravity, conductive and convective heat transfer). This is to prevent, and if necessary, mitigate the consequences of accidents should they occur.
Heat removal is also key to reactor safety. Holtec’s SMR-300 nuclear plant can keep all its nuclear fuel safe, cool, and undamaged within the reactor, spent fuel pool and integrated HI-STORM UMAX underground spent fuel storage canisters, in the case of any unforeseen catastrophic event. Under extreme environmental events, like the one that occurred at Fukushima, the reactor behaves like a simple, large, passively cooled heat exchanger. The same spent fuel storage safety principles are applied by Holtec at over 100 operating nuclear power plants around the world today.
As part of the UK GDA Process, Holtec is developing a generic Safety, Security and Environment Case (SSEC) comprising a Preliminary Safety Report (PSR), a Preliminary Environmental Report (PER) and a Generic Security Report (GSR) incorporating the safeguards case, which will be presented to the regulators for assessment.
Security & Safeguarding
Security
Ensuring the security of the SMR-300 plant is of paramount importance to Holtec. This means developing a design that keeps nuclear and radioactive material safe and secure against theft and sabotage within an ever evolving physical and cyber threat landscape, including the insider threat.
Holtec engineers are adopting a risk-based and holistic approach to the security of the SMR-300 which prioritises inherent security through ‘designing out’ vulnerabilities or otherwise through providing a blend of protective measures supplemented by procedural measures, with multiple layers of protection providing defence in depth. A robust security culture ensures that effective security is delivered.
This holistic approach is outlined in the Preliminary Security Report. The Generic Security Report in Step 2 will present the implementation of the approach during GDA.
Safeguards
We are committed to supporting the UK government to deliver its international obligations in support of the Non-Proliferation Treaty through the development of a through-life safeguards programme for the SMR-300. Its focus during the GDA is on safeguards by design and the development of the safeguards case.
The SMR-300 safeguards programme is outlined in the Step 1 issue of the Preliminary Safeguards Report. At Step 2 this will present progress in its implementation during GDA.
