Katmal Limited has now completed two years of operation. In that time we have worked for new build companies, a generation company, a nuclear dockyard, a decommissioning site and local authorities. Now looking forward to the next two years and looking for new customers.
The convention on nuclear safety’s aim is to “legally commit participating States operating land-based nuclear power plants to maintain a high level of safety by setting international benchmarks to which States would subscribe“. The UK’s 7th report to this convention is now available.
At 238 pages long it is not an inviting read but it is, nonetheless, quite interesting and provides a good overview of nuclear safety in the UK including a review of the regulations and the operations of the regulators.
An interesting quote (paragraph 16.23) is “Whilst REPPIR does not prescribe a specific probability to what is reasonably foreseeable, events with a frequency of 1×10(-5) to 10(-6) per year are considered, with any cliff edge effects from events of lesser probability also being considered“. ONR usually reframes from accepting any numerical value for “reasonably foreseeable”. This value puts it below the probability of any events listed in the National Risk Register which may surprise some people.
IAEA Nuclear Energy Series No. NW-T-2.8
This document published in March 2016 discusses the surprises that can occur when decommissioning nuclear facilities. It claims to be a good practice guide with expert opinion rather than recommendations made on the consensus of member states.
It explains that nuclear plant, particularly those with a long history, are not always built as recorded. It warns that: “When the nature of a decommissioning project is found to be substantially different to that expected, it often results in unplanned work to investigate and redefine the nature of the project, which may introduce delays and cost overruns, and which has the potential to expose decommissioning staff to additional industrial hazards and unplanned exposure to radiation”. A good decommissioning plan would consider the worst case and be ready to respond accordingly, considering it reasonably foreseeable that additional radioactive sources or contamination might be found or that the plant uncovered might not match the plans exactly and be ready to modify work plans and to protect the workforce against new hazards.
The authors provide a number of examples including finding bolts that were fully welded in place rather than spot welded thus defeating the equipment made to remotely remove the bolts. Other notable issues have occurred when trying to decommission the services to a building and accidently affecting supplies to neighbouring buildings. The finding of unexpected radioactive material or other hazardous material such as asbestos is also not uncommon.
Careful reading of records and investigation of the plant is recommended to characterise the plant and the radioactive inventory as well as possible to minimise the risks of unexpected issues.
The paper discusses the managerial mechanisms that are required to cope with the unexpected and show parallels with emergency planning. These include the ability to stop work on projects while issues are investigated and plans revised and require that the organisation is flexible enough to provide the necessary resource in a timely manner. A good stakeholder engagement plan is required to ensure that communications with groups such as the regulators and the public are appropriate.
Interestingly the report does not mention the role of the site’s Nuclear Safety Committee (see Ref for an ONR description of the NSC) in scrutinising decommissioning plans, hearing reports on progress and the response to issues, and challenging the Company to do better. In the UK this is a key supervisory role.
Much of the report is given over to case studies which provide valuable insight into the experience already gained in decommissioning nuclear facilities.
The report concludes that “Unknowns in decommissioning cannot be eliminated, regardless of the efforts applied. This is especially the case in old facilities where documentation may have been lost or where modifications were carried out without updates to reports. As a result, when planning for decommissioning, it is prudent to assume that such problems will occur, and ensure that arrangements are in place to deal with them when they arise. This approach will not only improve the efficiency of the decommissioning project, but will also improve the safety of the operations”.
This report is well worth a read for anybody involved in the decommissioning of nuclear facilities including safety case engineers, project managers, team leaders, the emergency/contingency planning teams and the regulators.
The Government have recently released a policy statement on Military Aid to the Civil Authorities (MACA) (here). This states that the military support to overwhelmed local authorities is provided from “spare capacity” and that “MOD does not generate and maintain forces specifically for this task … because … the requirement is unpredictable in scale, duration and capability requirement” and “experience suggests that requirements can usually be met from spare capacity“.
This is sensible and reasonable and, to date, very successful. During the 2007 summer floods in Gloucestershire floods the military responded to requests to help with over 1000 personnel deployed over an 11 day period. Helicopters and assault boats were used to rescue 193 people and reassure other cut off communities; Chinooks were used to transport a much needed high volume pump and aggregate and personnel filled sandbags, built barriers and distributed drinking water where the water board was struggling. (Pitt Review)
Recommendation 47 of the Pitt Review states that “The Ministry of Defence should identify a small number of trained Armed Forces personnel who can be deployed to advise Gold Commands on logistics during wide-area civil emergencies and, working with the Cabinet Office, identify a suitable mechanism for deployment.”
The government claims that this recommendation has been implemented (here) with the development of “the existing central response mechanisms” but in JDP 02 Operations in the UK: The Defence Contribution to Resilience you find that the military support is still described as “provided on an emergency basis and fielded from irreducible spare capacity“.
MACA is a valuable tool in the UK’s emergency response tool box and has been very effective on numerous occasions the fact that it is not obvious that Pitt Recommendation 47 has been fully implemented is a minor concern.
PHE-CRCE have published the latest of their really useful reviews of radiation dose in the UK. This publication data for 2010.
It shows that the largest contributor to the average UK dose is 1.3mSv/yr from Radon and Thorium which it describes as “ubiquitous”.
Patient exposure averages 0.44mSv/yr and occupational 0.0004mSv/yr.
The report concludes that the average doses assessed in this period are pretty much the same as was found in 2003.
Some advice on when to check your basements for radon is found in a later CRCE report.
The internet is becoming ever more full of really incredible real time data. I’ve just found a site that shows the sources of electricity used by the Bonneville Power Administration, Pacific Northwest of America (Site here). This shows power from thermal sources being pretty constant at 3000 – 4000 MW about 1000 MW below the overnight minimum demand. Wind power is shown as providing between no electricity and 4000 MW but there being no control over when it generates. Hydro is clearly the winning technology in terms of load following going from 4000 – 9000 MW on demand.
There are no surprises from this diagram but it does nicely show the variation in demand across the days and the inability of wind on its own to ever provide reliable power to an area. It shows thermal power providing base-load (nuclear can do that as well) and the need for “dispatchable” power. That is energy sources you can ramp up and down to follow demand. Hydro is very good for that. Batteries might be able to do it in the near future – but at a cost.
EDF’s Sizewell B played host to an OSART review 5th – 22nd October 2015 which has just published its findings.
OSART is the IAEA Operational Safety Review Team. Under this programme, which has been in existence since 1982, international teams of experts conduct in-depth three-week reviews of operational safety performance at individual nuclear power plants. These reviews are conducted at the request of the government of the host country. These “experts” are drawn from other nuclear power plant around the world. They provide the host station with advice and also take back to their home station a number of ideas about how safety can be improved drawn from the discussions with the host site and the other experts. A win-win situation.
The OSART team concluded that the managers of Sizewell B NPS are committed to improving the operational safety and reliability of their station. The team found good areas of performance, including, among others, a “well-developed and documented process to ensure that the emergency exercises comprehensively cover the situations that could arise during emergencies” and suggested that “the station should continue its programme of reviewing and updating severe accident management procedures across all plant areas and conditions, incorporating experience from the 2011 Fukushima accident.”
They thought that some of the conditions under which alerts were issued were too qualitative. Examples include “Emergency Services personnel are required to make access to a Radiological Controlled Area (RCA) in significant numbers”, “A significant increase in site radiation levels is observed”, and “An increase in containment radiological and/or environmental conditions is observed”. The station is encouraged to make all conditions for the classification of an emergency more quantitative rather than qualitative and specific to the Sizewell B station”. This doesn’t seem too serious a fault and easily rectified if the desire exists.
More interestingly the team report that “The process used by the station to assess off-site radiological consequences, transmit data and recommendations to the public authorities has not been optimized to reduce unnecessary delay”. This is an area where new technology keeps moving the boundary of the possible. There also seems to be a move away from the dose assessment expertise being within the operator’s company to being within the local authority and central government. The team’s suggestion is that the dose-rate measurements taken on the site fence by the Emergency Perimeter Gamma Monitoring System (EPGMS) can be provided in real-time to the local authorities to “measure the extent of radiation contamination around the site”. They also suggest that an Operational Intervention Level could be put on EPGMS to lead to a declaration. In the past both of these moves have been resisted because the EPGMS measures external radiation dose whereas most of the public exposure results from inhalation of the plume and, unfortunately, there isn’t a usable relationship between the two unless you make assumptions about the isotopic and physical composition of the releases. EPGMS will react to noble gases such as 41Ar, which have virtually no public dose implications, but not to some actinides which can lead to high doses. It may be worth having another look at this issue.
You sense that international teams are uncomfortable with the UK planning philosophy of planning in detail for the worst reasonably foreseeable fault and having outline plans to manage less likely but more severe faults. They state that “The UK approach is for these detailed plans to provide the basis for a more extensive response to even less likely but potentially more severe consequences (what the UK refers to as “extendibility”). This approach meets UK regulations but is different to that used in most other countries who base plans on events involving severe damage to the reactor fuel”. They then suggest that “the station should consider benchmarking its methodology to conducting emergency planning hazard assessment against the methodology used by similar stations in other countries to ensure that events involving severe damage to the reactor fuel are adequately addressed in emergency plans”. Which seems to suggest that they consider turning their back on UK regulation and advice. In truth there isn’t as much difference as this might suggest. There is a national programme underway at the request of DECC (now Department for Business, Energy and Industrial Strategy) and the Scottish Government to review the ability of local authorities to extend countermeasures to protect the public in the event of a severe nuclear accident. What is important is that we have a system for ensuring that proportionate arrangements are made for the whole range of accidents that are conceivable. This should be kept under continuous review but I don’t believe that the UK is getting this area wrong. The current UK system is explained in Appendix D of the Governments’ Nuclear Emergency Planning and Response Guidance.
ONR reported that “the IAEA OSART mission presented an overview of its findings to EDF NGL, ONR and Department of Energy and Climate Change (DECC) at the mission exit meeting. The mission identified recommendations, suggestions, good practices and good performances. Recommendations were included in the areas of operations, maintenance and operating experience feedback. EDF NGL has responded positively with a commitment to take action in regard to the recommendations with associated action plans”.
And the government concluded that “The Department for Business, Energy and Industrial Strategy welcomes the report from the IAEA and looks forward to a further follow up Mission conducted by the IAEA in 2017. The UK is confident that good progress will be made by EDF Energy on the further enhancements suggested by the IAEA and recognises the positive feedback provided by IAEA on the operational safety of Sizewell B”
Contrary to what some may think the nuclear industry is always ready to hear constructive, expert feedback on their operations. OSART visits are exhausting for the visitors and hosts alike but play an important role in improving nuclear operational safety around the world. This visit to SZB has raised some points about their emergency preparedness and response but is generally impressed and supportive. There will be an OSART follow up review at Sizewell B in the first half of 2017.
The success of OSART recommendations can be judged from the Figure taken from the OSART pamphlet which shows the resolution of issues raised by the time of the follow up meeting which is usually about 18 months after the visit.
EDF have launched a competition to develop new techniques for inspection of nuclear power plant and wind farms. Check it out if interested, the EDF Energy inspection Innovation Challenge.
If you’ve got a spare 117 Billion Pounds (GBP) then you could take over the job of decommissioning the UK’s nuclear liabilities (17 sites in 120 years). That’s a lot of money! (See here).
This report is the MOD’s response to a consultation about where the used Reactor Pressure Vessels (RPVs) from decommissioned nuclear submarines should be stored for the next few decades.
It seems that there was little to choose between the handful of sites considered “Site assessments concluded that all five of the shortlisted sites were suitable and able to safely and securely store the RPVs”.
Capenhurst was identified as the best option largely because they already have a suitable building so the planning process will be easier.
See news release here.