Editor: Colin Potter, Nuclear Directorate, HSE, Rose Court, 2 Southwark Bridge, London SE1 9HS
On 16 May 1997, an important top-level meeting took place between senior representatives of all the UK's nuclear licensees and senior staff of HSE, plus the Chairmen of HSC and ACSNI. When I conceived of this meeting last summer, my first objective was to bring all the licensees together to allow them to understand the range of each others' activities and the calls that they each make on ND's resources. I wanted to share ND's view of the future with them so that we could check our vision, and the priorities arising from it, against the future visions of their parts of the UK nuclear 'industry'.
My other major objective for this meeting was to look at how we might improve the efficiency and effectiveness of the interface between ND and its licensees. That is certainly necessary for ND, with the continuing pressure on our resources, but it is also, I believe, vital for all parts of the nuclear 'industry' as it faces up to the challenges of the next 5-10 years and beyond. These challenges are not just commercial and organisational, but relate also to the perceptions of parliament, the media and the public about how we should go about our business in the new era of increasing openness.
While the top-level safety objectives of HSE and the licensees are undoubtedly very similar, licensees have quite distinct sub-objectives, such as survival, making a profit, creating employment, which we do not share. In her opening remarks Jenny Bacon, HSE's Director General, made it clear that, while HSE/ND would do everything possible to make the interactions with the licensees efficient and effective, our fundamental business is to regulate and enforce the licence conditions and other statutory requirements, not to act as a facilitator for the UK nuclear industry. She also warned the industry leaders that HSE/ND would not be prepared to make good any technical shortcomings that might arise from their current downsizing exercises.
A number of other issues were discussed in depth during the meeting, particularly the need for the industry to prepare itself for an ever-increasing level of openness about its safety cases and operations. Overall, this was a valuable and positive meeting with the licensees and we shall review the lessons learned from it to see whether it would be worthwhile repeating in future. My thanks go to all those who participated in the meeting and especially to the ND staff who organised it so successfully.
Dr S A Harbison
HM Chief Inspector of Nuclear Installations
In February, HSE's Nuclear Installations Inspectorate (NII) granted agreement for Sizewell B nuclear power station to undertake automatic frequency responsive operation (AFRO) during the current cycle of operation, which will continue until the next refuelling outage planned for later this year. Sizewell B is operated by Nuclear Electric and it has a pressurised water reactor (PWR), the only one of this type constructed in the UK for commercial power generation. AFRO will be an additional mode of operation to the established base load mode and will be undertaken in agreement between Nuclear Electric and the National Grid company.
In the AFRO mode, the station contributes to controlling the frequency of the electricity supply on the national grid by automatically adjusting plant power output to compensate for fluctuations in grid frequency. These fluctuations occur due to continually changing demands for electricity from the grid. A common example is the so-called 'TV peak', when there is a sudden surge in demand for electricity at the end of popular television programmes. The increased demand causes the grid frequency to drop slightly, which needs to be counteracted by adjusting the supply onto the grid from generating stations.
NII has assessed the safety case produced by Nuclear Electric to justify operation in the AFRO mode. This safety case is specific to the current (second) cycle of operation. NII is satisfied a systematic review has been carried out on the impact of AFRO on the station operational safety case and there is adequate justification to support this mode of operation. NII is also satisfied that revised operating procedures have been put in place to encompass AFRO, and station operating staff have been trained in their use.
Before AFRO can be undertaken in subsequent cycles of operation at Sizewell B, the further agreement of NII will be required. Operating experience during the second cycle will be taken into account.
The MoD sites at Aldermaston and Burghfield, operated under contract by Hunting BRAE plc, are due to be licensed later this year. For a nuclear site licence to be granted by HSE it is necessary, among other things, for the prospective licensee to demonstrate that they have the necessary safety management systems in place to address conditions attached to the licence. The company licence condition arrangements have been examined by HSE for adequacy and inspections have been carried out by the site inspection team to assess their effectiveness at the workplace.
A key requirement is the need for the prospective licensee to prepare safety cases for all operations on the Aldermaston and Burghfield sites. All the necessary safety cases have now been submitted to HSE and these are being examined in line with our assessment strategy.
Hunting BRAE plc has prepared decommissioning and waste management strategies for the sites to satisfy government's policy and set the framework for complying with the appropriate licence conditions. These strategies have been judged to be acceptable by HSE although further work is still required to support their implementation. NII require detailed decommissioning programmes for a number of the facilities prior to granting the licence.
As part of the licensing process, Hunting BRAE has been required to consult with local authorities and any safety related matters arising from these consultations will be considered by HSE/NII prior to granting site licences.
On 3 March, NII were informed by Scottish Nuclear Limited that an event had occurred at Hunterston B, in which reactor gas had reached operational storage tanks which normally hold supplies of fresh carbon dioxide. Checks carried out by the station management indicated that there was a potential for some of this mildly contaminated gas being carried off-site via the road tankers that replenish the station's supplies.
An on-site investigation into this event was immediately instigated by NII. As this event was also of concern to the Scottish Environment Protection Agency (SEPA), a joint team was set up. There was significant media interest, particularly in Scotland, and a Statement was made by the Secretary of Sate for Scotland in the House of Commons on 5 March. A joint NII/SEPA interim report was produced and sent to the Scottish Office on 12 March. The NII/SEPA team continued to follow up the event and are currently finalising their conclusions and recommendations. Arrangements at other stations have also been reviewed to ensure that a similar incident could not happen elsewhere.
An update on the event will be provided in the next Nuclear safety newsletter. This will give the findings of the investigation and the actions taken by the licensees.
As part of their arrangements for responding to an emergency on the Sellafield site, BNFL has for some time used a District Control Centre (DCC) set up as required within existing facilities at its Summergrove complex, a few miles from the site. The purpose of the DCC, in the event of a Sellafield emergency being declared, is to enable the overall co-ordination of the off-site response by a management team located in the centre. A wide range of local and national agencies would attend the DCC in the event of an emergency, including representatives from NII.
While this arrangement has functioned satisfactorily during emergency exercises, the potential benefits of a purpose-built facility have been recognised by all parties involved in manning the centre. BNFL has therefore recently completed the construction of a purpose-built facility at Summergrove.
Prior to seeking NII agreement to declare the building operational, BNFL invited interested parties to visit the DCC for familiarisation purposes and to comment on the suitability of the facilities. About 200 people from various agencies took the opportunity to visit the centre. A group from NII visited the DCC and associated media briefing centre located in the nearby Whitehaven School in February. Following this visit, NII agreed to the facility becoming operational on 1 March 1997.
The centre is now available for use as required in the event of an emergency at Sellafield, or more likely during emergency exercises involving the demonstration of the off-site response capability. The first of these exercises is to be a recovery phase seminar, which will consider the longer term issues which might arise following an emergency. This will be followed by the national emergency exercise based on Sellafield which is to take place in October this year.
The application from UK Nirex Ltd to construct a Rock Characterisation Facility (RCF) at Sellafield has been rejected by the Public Inquiry and the Secretary of State for the Environment. This will delay the development of a final disposal route for Intermediate Level Waste (ILW) and has implications for the packaging and storage of waste at licensed sites. Prior to the decision over the RCF the first emplacement of waste in Nirex's deep waste repository (DWR) was scheduled to take place in 2012.
Licensed sites already have a number of ILW stores, and are developing further purpose-built designs. However, the decision on the RCF means that this waste is likely to be stored for longer, and also the amount of waste requiring to be stored will increase. This will inevitably mean the provision of new stores and replacements for existing facilities at Sellafield and other licensed sites, requiring both planning permission and licensing. As with the storage facilities, the specifications for the packaging of some of these wastes will need to be examined in the light of extended storage requirements. This requirement for extended storage may also effect the licensees' current radioactive waste management and decommissioning strategies and plans. In addition to these issues, the funding arrangements will need to be considered by HSE and the licensees.
Although HSE's Nuclear Directorate (ND) is considering the implications of various options, a firm position may not be reached in the near future. ND needs to await any changes in Government policy following the Nirex decision and any future proposals by DoE or Nirex.
Magnox Electric has successfully removed samples from one of the Reactor Pressure Vessels (RPV) at Trawsfynydd. The samples are the full 100 mm thickness of the RPV wall and will provide fracture toughness and metallographic data of relevance to the structural integrity safety cases of the operating stations with steel RPVs. The sample removal is a significant achievement as all the access and cutting operations have been carried out remotely: the RPV cutting was by an ultra high pressure water jet. Four samples have been removed from one submerged arc weld and none have been found to contain significant defects. Sampling of another weld is due to start shortly.
Trawsfynydd's twin reactors were closed down in July 1993 on economic grounds and the station is now well into decommissioning. Detailed examination of the RPV samples should enhance understanding of the effects of radiation on welds used to construct the vessel.
Two Improvement Notices were served in February concerning obsolete criticality detection systems in buildings D1202 and D1203 on the United Kingdom Atomic Energy Authority (UKAEA) site at Dounreay. These systems fall well short of modern standards and are becoming increasingly difficult to maintain. While the UKAEA had recognised their obsolescence in the 1980s, there were no plans for replacement systems in place at the time of the NII inspection. UKAEA have now begun replacement installations.
New nuclear site licences have been granted by HSE in respect of the Royal Dockyards at Rosyth and Devonport. The dockyards carry out refuelling and refitting activities for the Royal Navy's fleet of nuclear submarines. The new licences have been necessary because under privatisation of the dockyards, the contracting arrangements between MoD and the dockyard companies change. In each case a new corporate body is using the site.
The licence for Rosyth granted to Rosyth Royal Dockyard Limited (RRD) came into force on 30 January, while the licence for Devonport was granted to Devonport Royal Dockyard Limited (DRD) on 13 March. All nuclear-related activities on the two licensed sites will now be under the control of RRD and DRD respectively.
HSE's Nuclear Installations Inspectorate (NII) has assessed the new licensees' proposals and inspected aspects of their implementation. Normal site inspections have been used by NII to inspect particular aspects, including emergency arrangements, operational safety cases and licence condition arrangements. RRD and DRD have both demonstrated appropriate organisational structures and the required safety arrangements.
In August 1996, HSE's Nuclear Directorate (ND) was reorganised into a three Division structure. Prior to that the Directorate had five Branches, two assessment Branches, two inspection Branches and one covering policy, international work, finance and planning. Each ND Division is managed by a Deputy Chief Inspector as follows:
The Division is headed by Chris Willby and consists of eight Units covering finance and planning, Director's Office, strategy, management systems, research, reactor and chemical plant projects and human resources.
Headed by Dick Pape, with seven specialist Units covering accident analysis, mechanical and process engineering, radiological protection and radioactive waste management, control and instrumentation and electrical systems, structural integrity, civil engineering and hazards, and management of safety.
Jim Furness heads this Division which has six Units covering inspection of BNFL, operating Magnox sites, British Energy, MoD sites, decommissioning reactors and UKAEA sites, and other smaller licensed sites.
Nuclear safety policy work is now undertaken by HSE's Safety Policy Directorate, while policy work on Ionising Radiations has been transferred to the Health Directorate.HSE is the prime sponsor of the NESC (Network for Evaluating Steel Components) project which is an international network comprising over 20 partners. The object of NESC is to carry out a large scale test upon a stainless steel clad cylinder made from pressure vessel steel with artificially induced defects. A series of pre- and post-test inspections are carried out by test teams who don't know the locations and sizes of the defects and a series of stress and fracture analyses are carried out using the inspection results. The NESC project thereby aims to explore the accuracy of the whole structural integrity assessment process. After about five years of planning the test was actually carried out at AEA-T's spinning cylinder facility at Risley, Cheshire on 20 March 1997 where the test cylinder was successfully subjected to simulated pressure loads and a significant thermal shock. The post test inspections will now be carried out. We hope to provide more details in the next Nuclear safety research newsletter later this year.
International Standard Problem No:38 (ISP38) final workshop was held at the HSE Head Office in London on 8 and 9 April 1997. More than 20 international organisations participated in the exercise. ISP38, which started in September 1995, was led by AEA-T, sponsored by HSE, with the assistance of Tractabel, Belgium, and CEA of France.
The main aims of ISP38 are to establish the validation status of thermal-hydraulics computer codes used to predict the transient sequence of events associated with certain faults in pressurised water reactors. CEA provided the data from a test based on the loss of the residual heat removal system in the BETHSY integral test facility at Grenoble.
The final comparison report will be presented to the OECD's Nuclear Energy Agency by December 1997.
As mentioned in the last issue, HSE is supporting a proposal to establish an International Nuclear Regulators Association (INRA). Although many nuclear regulatory organisations already have arrangements for bilateral discussions, at a meeting in Washington in January it was agreed that there is a justifiable need for a wider forum of the most senior regulators. It is proposed that INRA will be informal in structure and allow for free and open discussions of high level regulatory policy issues.
It was agreed that the initial membership should be kept quite small as it was felt that the group must first demonstrate that it can work effectively before expanding. Currently the proposed membership is limited to the United States, France, UK, Canada, Spain, Japan, Germany and Sweden.
On 17 April, the UK participated in an international emergency exercise, built around a hypothetical accident at the Loviisa nuclear power plant in Finland. The exercise was sponsored by the OECD Nuclear Energy Agency (NEA) and was the second in a series of exercises, designated INEX-2, involving nuclear facilities in OECD countries. The series started with an exercise based on an accident scenario at a Swiss nuclear station in 1996 and will continue with further exercises in Canada and Hungary in 1998.
The prime objectives of the INEX-2 series of exercises are to test: national and international communications systems; decision making on protective actions; and the mechanisms for communication of information to the public.
In the UK, the Department of the Environment takes the lead in determining the national response to nuclear accidents overseas. The response was based on the National Response Plan and the use of the UK-wide Radiation Incident Monitoring Network (RIMNET). Although the full National Response Plan was not activated, the exercise confirmed the adequacy of those functions of the Plan that were tested.
ND has been the UK representative on the NEA Expert Group on Emergency Matters, which devised the INEX series of exercises, for a number of years.
In February, Dr Sam Harbison, Director of ND, met Alexander Smyshlyayev, Head of the Ukraine Nuclear Regulatory Administration. Apart from discussions on nuclear safety regulation, the meeting was also used to sign and exchange a formal Information Exchange Agreement (IEA).
In April, a new IEA was signed and exchanged with the Nuclear Safety Inspectorate of Hungary. This IEA will run for an initial five year period, and we hope that the first formal meeting between the two Chief Inspectors will take place later this year.
The signing and exchanging of these two IEAs brings the number of countries with which ND has formal arrangements to twelve. We hope to sign and exchange new IEAs with China, the Czech Republic and the Republic of Korea during this year.
Since the last issue ND has been particularly busy with the EC funded assistance programmes to Bulgaria. During February ND inspectors spent a week in Bulgaria with Bulgarian regulators addressing regulatory practice for in-service inspection. The Bulgarians involved with this particular topic are due to make a return visit to the UK in June to continue exchanges. Also in February, Bulgarian regulators visited the NII office in Bootle and Hunterston 'A' to discuss decommissioning.
Then, in April, two further visits were made by ND personnel to Bulgaria to address 'Probabilistic Safety Analysis assessment methodology' (in conjunction with Belgian colleagues) and 'Project management of periodic safety reviews'. Again, there will be a return visit to the UK in June.
In May, also in conjunction with Belgian colleagues, an ND inspector visited Bulgaria for exchanges on radiation safety.
Since the last Nuclear safety newsletter, HSE has issued a quarterly statement of incidents at nuclear sites covering the period October to December 1996. Normally, each incident mentioned in HSE's quarterly incident statement will have already been made public by the licensee or site operator, either through a press statement or by inclusion in the site newsletter. The only incident included in the statement is briefly described below. The rating of the incident on the seven point International Nuclear Event Scale (INES) is also given. Single copies of the full statement are available free from HSE (see Further information).
On 11 November 1996 station staff noticed that there had been a movement of a section of cold reheat pipework, which is pipework which transfers steam from the main turbines to the boilers for reheating. No people were injured and no contamination was released. Investigations have shown that the movement had occurred as a result of condensate build up, during restart of the reactor after a refuelling outage. NII have placed a number of requirements on the station to address the circumstances which led to the incident. The incident was rated as INES level 1.
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At the March meeting of HSC's Advisory Committee on the Safety of Nuclear Installations (ACSNI), NII reported on the safety issues arising from the periodic safety reviews of reactors. The Chief Inspector, Dr Sam Harbison, assured members that the reviews did not mean an automatic right for stations to continue operating for another 10 years; all stations continued to be reviewed for operational safety on a regular basis. Members endorsed the reviews as providing a systematic process for submission and assessment of safety cases linked to specific objectives.
Nuclear Electric reported progress made toward achieving its target efficiency savings, and NII explained how it was monitoring the effects of these measures. ACSNI's Review Group looking at safety management issues was asked to consider in more detail the effects of reductions in staffing on morale and safety.
ACSNI also agreed the advice to the Commission on the scope and content of its 1997-98 programme of research and looked at the programme for implementing the emergency planning provisions in the COMAH and Basic Safety Standards Directives.
The Committee will be visiting Devonport Royal Dockyard during July to see the nuclear submarine refitting facilities.
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Printed and published by HSE, June 1997.