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Katmal Limited has been supporting the nuclear industry and local authorities since 2014. It which time it has completed a number of projects for a range of customers.

Progress towards REPPIR 2019 implementation

I am interested to see what impact on DEPZs we see following the introduction of REPPIR-19 and the bizarre way they are now set. With REPPIR-01 the size and shape of the DEPZ was in the gift of the ONR who had a cumbersome process covering technical, practical and strategic issues (see here). They had detailed discussions with the operator about the site’s safety case and the potential for accident. In this discussion both sides fielded teams of experts, well versed in safety cases and nuclear emergency plans. These discussions could take years....

In REPPIR-19 the safety case still exists and is still discussed at great length between the teams of experts within the operator and ONR organisation. This is a never ending cycle of review and revision.

Under regulation 4 of REPPIR the operator “must make a written evaluation before any work with ionising radiation is carried out for the first time at those premises” (a later clause includes continuing work) and must be “sufficient to identify all hazards arising from the work which have the potential to cause a radiation emergency”. The operator must provide “details of the evaluation” to the ONR. We start to move away from the safety case. Intriguingly this regulation does not require the ONR to bless the work but we can safely assume that if they think it substandard they will require a discussion and a revision. Can’t we?

Under regulation 5 the operator must make an assessment to consider and evaluate a full range of possible consequences of the identified radiation emergencies. This also goes to the ONR but, again, no blessing is mentioned in the regulation.

Regulation 7 requires that the operator produce a consequence report and send it to the local authority. This report is not even a précis of the large body of work that has gone on before. It tells the local authority where the site is, recommends a minimum size for the DEPZ, and discusses which protective actions may be required promptly and how far downwind they should go. This is a very brief document.

Regulation 11 then requires the local authority to consult with a range of organisations and set a DEPZ. What seems to be happening is a local authority officer writes a paper for the council setting out the options (in some cases that might be “this is the proposed DEPZ accept or reject?”). This is discussed at a meeting at which it may not be the only matter to discuss and either rejected or accepted. Did I mention that the local authorities were given a matter of weeks between receiving the consequence reports and having to set the DEPZ by law?

So setting the size of the DEPZ has gone from being in the remit of the national regulator, with teams of experts and able to take their time and apply the same policy uniformly across the UK, to a rushed decision by local authorities who are reassured in the guidance that they don’t need to understand the technical background to the subject.

AWE (Burghfield and Aldermaston

AWE operate two sites near Reading where they support the UK nuclear deterrent programme. The work at AWE covers the entire life cycle of nuclear warheads; from initial concept, assessment and design, through to component manufacture and assembly, in-service support, and finally decommissioning and disposal

Two consequence reports have been published on the internet.
Burghfield and Aldermaston in addition the paper written for consideration by the local authority is available on the internet.

The Burghfield report recommends that the proposed minimum geographical extent to be covered by the Local Authorities Off-Site Emergency plan is an area extending to a radial distance of 3160m from the Burghfield Site centre location which compares with the old DEPZ of 1.3 - 2.1 km from the site.

For Aldermaston the new advice is for a minimum DEPZ of 1540 m from the Aldermaston Site centre location compared to the old 2 km - 3.5 km.

AWE current off-site plan (2019) here.

Public information leaflet (2020) here


BAE Systems Barrow is a manufacturing and design facility for nuclear-powered deterrent and hunter-killer submarines.

REPPIR-19 compliance delayed by Covid response now expected 21 November 2020 here (para 37).

Current public information is available here

Current DEPZ - Barrow.


Capenhurst is a uranium enrichment site operated by Urenco. It uses centrifuge technology and holds significant stocks of Uranium Hexafloride, representing a chemo-toxic hazard as well as a radiation hazard.

The report on the REPPIR-19 DEPZ determination by the local authority can be found here . This is defined by a number of roads which ring the site beyond the 800 m distance recommended by the operator.


The outline planning zone is the default 5 km.

The consequence report (written by Keith Pearce) can be found here.

Public information here.


Devonport contains a nuclear licensed site (DRDL) and a nuclear authorised site (HMNB). The consequence reports can be found here (DRDL) and here (HMNB). Unsurprisingly, since the major accident risk comes from operating submarine cores, the hazards and distances for urgent protective actions are the same as for the operational berths.

DEPZ Devonport.

An outline planning zone exists for the site and for a couple of buoys here

The off-site plan can be found here
Public information here.


Dounreay in Caithness was the UK's centre of fast reactor research and development from 1955 until 1994 and is now being decommissioned and cleaned up.

No information found as of 2/10/2020 but public information is linked from here and the revised material might be slotted in here when ready.

Off-site plan (2018) available here

Dungeness B

Dungeness B is an EDF Advanced gas cooled reactor site in Kent. It has a decommissioning Magnox reactor site next door that does not have a REPPIR plan.
The local authority discussion report can be found here and their record of decision here.

In the CR EDF recommended a minimum DEPZ extent of 1 km. The council decision report states that: "these discussions concluded that the current 2.4 km DEPZ was the most practical layout to administer and that stakeholders, including local residents, were familiar with this established configuration".

Basically the decision made is the path of least resistance. Will PHE consider this to be an "excessively large area" (Guidance paragraph 197)?

Public information available here.



Hartlepool is an EDF Advanced gas cooled reactor site in Cleveland.
The EDF consequence report (here) recommends that the DEPZ be no smaller than 2 km from the centre point of the two reactors. The revised DEPZ agreed by the local authority (here) extends for approximately 2.7 km from the site. The New DEPZ area now includes 6 COMAH sites as well as the industrial estates of Graythorpe, Tofts Farm East and West and 1 residential property. The boundary of the DEPZ reflects physical features such as roads, rail, footpaths and geographical boundaries.

The OPZ public information leaflet can be found here.


Hinkley Point B

The CR is available here. A great deal of information about how this was produced is presented in a EDF report (here). The CR recommends and DEPZ of 1 km and for the taking of stable iodine and shelter to be implemented in this area as soon as practical after the declaration. This compares to the current DEPZ of 3.5 km, which is a hang over from the Magnox station at Hinkley Point A. The local council have responded (here). "Whilst Somerset County Council accept the technical assessments provided, we believe any rationale for future arrangements regarding radiation emergencies must include the views of local communities. As such, no reduction will be made to the current arrangements unless the will to do so is widely expressed by those communities within the current detailed emergency planning zone, up to 3.5km from the site"

Given the news that Hinkley Point B is to cease generation by July 2022 (here) this may not happen until shutdown.

It is maybe surprising that the ONR and PHE seem content with a DEPZ that is about 10 tens the size it should be.



Heysham is an EDF Advanced gas cooled reactor site in Lancaster. It comprises Heysham I and Heysham II, each with two reactors.

The REPPPIR-19 documents are available here

The revised DEPZ was agreed by Lancashire County Council on 5 March 2020 and is based upon the recommendations contained within the EDF Energy Consequences Report. The DEPZ is approximately a distance of up to 2.3km from the site.


Hunterston A

Hunterston A is a decommissioning Magnox site in Ayrshire. It is a surprise to see it a consequence report for the site, but it recommends that no off-site plan is required for the site, which is no surprise.

The CR discusses the possibility of a member of the public receiving doses above the lower ERL for shelter in the event of a large aircraft crash onto one small facility on site. The company make the credible claim that this is very unlikely and that the resulting smoke would probably cause the public to withdraw.

CR available here.

Hunterston B

Hunterston B is an EDF Advanced Gas Cooled Reactor site in Ayrshire. The consequence report from EDF can be found here

EDF recommend that "The Detailed Emergency Planning Zone for the site be no smaller than 2 km from the centre point noted". They also recommend the urgent protective actions of stable iodine and shelter out to this distance, to be implemented "as soon as is practical". The assessments indicate evacuation is justified within 300 m, but since most of this is on-site a detailed plan for urgent implementation is claimed not to be justified.

EDF also recommend that food controls be placed within 24 hours for a distance of 43 km downwind.

The local authority briefing paper (here) concludes that "there are two realistic options. Firstly, to go with the Operator’s recommendation of 2 km, the reasonableness of which has been confirmed by Public Health England. Alternatively, to retain the current properties within the boundary, having regard to the communication and certainty advantages which such a long-standing boundary brings in an emergency. In both cases the boundary would now be aligned with geographic features, rather than being a simple circle around the site.

The local authority have reached an "interim decision" to leave the DEPZ as it is until they can devote more process to its consideration after the pandemic stops dominating resources (see here).
Hunterston current off site plan here.


Operational Berths are those berths that have been approved for the use of Nuclear Submarines.

The consequence report for Portland can be found (here). The CRs for all the other OBs are likely to be near identical.

The recommendation is for a 1.5 km DEPZ centred on each berth.

The prompt protective actions recommended are:
a. 200 m from the submarine in all directions - controlled evacuation of the immediate area around the submarine.
b. 400 m from the submarine in all directions – personnel to shelter indoors within the first few hours.
c. 1.5 km from the submarine in the downwind sector - provision and consumption of stable iodine tablets (SITs) within the first few hours.
d. 1.5 km from the submarine in the downwind sector - sheltering indoors within the first few hours

It is recommended that the declaration of an Off-Site Nuclear Emergency by the operator to the local authority is the trigger for implementing the off-site emergency plan and initiating all of the above recommended urgent protective actions.

Portland no change to DEPZ (here).

Clyde CR here. Clyde off-site plan (HM Naval Base Clyde and the Faslane, Coulport and Loch Goil Berths) here.

Loch Goil - DEPZ 1.5 km circle with one lump to the north here.
Faslane - DEPZ 1.5 km circle with lumps and bumps here.

Southampton - DEPZ 1.5 km with lumps and bumps (no change) here.
Off-site plan (2018)(shared with portsmouth) here.

Portsmouth DEPZ covers three areas of roughly 1.5 km in radius, including parts of both Portsmouth and Gosport here.
Off-site plan (2018) (Shared with Southamption) here.
Public information here.

Rolls Royce Submarines

Rolls Royce submarines has two Nuclear Licensed Sites at Raynesway on the outskirts of Derby, the Neptune Site and the Nuclear Fuel Production Plant (NFPP) site. Their consequence report can be found here


The recommendation is for a DEPZ of at least 330m from some identified points on site leading to a "lobe shaped zone", as shown in the figure above taken from the CR. In addition an outline planning zone of 1 km has been specified by the Secretary of State for Defence in accordance with regulation 9(1)(c).
The recommended minimum area is smaller than the preceding DEPZ.


The consequence report can be found here. A distance of 5.3 km is recommended for the minimum geographical extent for detailed emergency planning around the Sellafield nuclear licensed site based on a severe earthquake affecting the site.

Current public information found here.

Sizewell B

The consequence report from EDF can be found here and the PHE response to it here.

EDF recommend that "The Detailed Emergency Planning Zone for the site be no smaller than 1350 m from the centre point noted". They also recommend the urgent protective actions of stable iodine and shelter out to this distance, to be implemented "as soon as is practical". The assessments indicate evacuation is justified within 250 m, but since most of this is on-site a detailed plan for urgent implementation is claimed not to be justified.

It is reported (here) that PHE had correspondence with EDF and at least one meeting in support of its review of the EDF CR and leading to the conclusion that "PHE are confident that the application of the Emergency Reference Levels in deriving the recommended distances is correct." The PHE report states that the indicated distance for shelter is 500 m but that "where practical the minimum technical distance for the implementation of sheltering and stable iodine prophylaxis should be the same". It may be sensible at the planning stage not to have different protective actions at different distances but even that is debatable, you may be advising someone at, say, 1200 m to shelter when you suspect that it is likely to avert less than the lower ERL for shelter - how do you justify this? Whatever you think about that, EDF should not be closing done the debate in the technical document. EDF's duty was to report the distances suggested by purely technical arguments.

The council discussion paper and the decision can both be found here.

The decision was:
a) the Sizewell Detailed Emergency Planning Zone as set out in Appendix A (solid blue line).
b) that the revised Sizewell off site emergency planning arrangements should include:
i) sufficient detail to fully implement evacuation to 4kms (2.5mile) or shelter and/or stable iodine tablets to 15km (9.3 mile) within 12 hours of a radiation emergency being declared (the current Extended Emergency Planning Zone); and
ii) sufficient detail to allow evacuation or shelter and stable iodine to begin being implemented up to 30km (18.6 mile) within 24 hours of a radiation emergency being declared (the new Outline Emergency Planning Zone);

Sizewell Off-site plan (2018) here.



At Springfields Uranium Hexafluoride (UF6) is produced following a number of chemical processes in two sets of rotary kilns and a fluidised bed reactor. HF and F are used as feed gases in these processes introducing some other hazardous materials into the process.

The consequence report from Springfields can be found here. This recommends "Sheltering within the DEPZ to protect against addition ionisation from a criticality in accordance with the lower ERL for shelter of 3 mSv."

The DEPZ is defined as a land area that varies from approximately 300 metres to 1.4 km from the boundary of the Springfield’s Fuels Ltd. site, which is defined by roads, footpaths, field boundaries and waterways. The area includes the villages of Lea Town and Clifton. The council decision is posted here.

The REPPIR prior information for those in the DEPZ is posted here and the REPPIR prior information for the OPZ here.



The consequence report from EDF can be found here.

EDF recommend that "The Detailed Emergency Planning Zone for the site be no smaller than 2 km from the centre point noted". They also recommend the urgent protective actions of stable iodine and shelter out to this distance, to be implemented "as soon as is practical". The assessments indicate evacuation is justified within 300 m, but since most of this is on-site a detailed plan for urgent implementation is claimed not to be justified.

This compares with the current 3 km DEPZ as shown in the 2019 off-site plan (here).

EDF also recommend that food controls be placed within 24 hours for a distance of 43 km downwind.
Not yet found council decision or new off-site plan.



An ONR report here reports that the site is fuel free and has confirmed to the regulator that it considers that REPPIR-19 no longer applies to its operations on site and that no duties fall on its local authority.

ONR have accepted this. Henceforth Wylfa will have no DEPZ.

How does the Wylfa DEPZ cease to exist if an ONR PAR states that it does exist under REPPIR 2001 and the site does not have to submit a CR under REPPIR-19 for the new duty holders, the local authority, to consider and decide that one is not needed?

General advice for the public about Nuclear Emergencies published by PHE can be found here.

Page last revised 24/12/2020