STUDSVIK UK LIMITED ENSREG Stress Tests : Final Report REVISION SHEET Rev. Description Revised By Checked By Approved By A Original copy ER DS MM Studsvik Report Reference: TR_MRF021 Revision: Rev A Date: December 2011 Technical Report Studsvik UK Limited 1 Joseph Noble Road Lillyhall Industrial Estate Workington Cumbria CA14 4JX Page 2 of 37
CONTENTS 1 INTRODUCTION... 4 2 BACKGROUND... 4 3 INITIATING EVENTS... 5 3.1 FLOODING... 5 3.2 EARTHQUAKE... 6 3.3 OTHER EVENTS... 7 4 CONSEQUENCES OF LOSS OF SAFETY FUNCTIONS FROM ANY INITIATING EVENT CONCEIVABLE AT THE MRF... 7 5 SEVERE ACCIDENT MANAGEMENT ISSUES... 8 6 CONCLUSIONS... 8 7 REFERENCES... 9 APPENDICES... 10 1 INTRODUCTION Following the accident at the Fukushima Dai-ichi nuclear power plant in Japan, the European Council declared that the safety of all EU nuclear plants should be reviewed, on the basis of a comprehensive and transparent risk assessment ( stress tests ). The European Nuclear Safety Regulatory Group (ENSREG) and the Commission were invited to develop these tests in a coordinated framework taking account of the lessons learned from the accident in Japan and with the full involvement of Member States and making full use of available expertise (notably from the Western European Nuclear Regulators Association [WENRA]). Appropriate stress tests were agreed by ENSREG and the European Commission, as shown in Appendix 1. These Stress Tests closely reflect the proposals put forward by the Western European Nuclear Regulators Association (WENRA). The UK Government and the Office for Nuclear Regulation (ONR) have an on-going commitment to the continuous improvement of safety at all nuclear facilities. Therefore, whilst the focus of the EU stress tests is on nuclear power plants, the ONR extended the applicability of these tests to all UK nuclear licensed sites, to the extent that the tests are appropriate for each facility, See Appendix 2. This report provides details of the assessment for the Studsvik Metal Recycling Facility (MRF) which is a nuclear licensed site located in Lillyhall, Cumbria. The assessment has comprised a number of interactive reviews involving personnel from the MRF and across the wider company. The report is structured in accordance with the ENSREG specification and includes the three main stress test headings. a) Initiating Events b) Consequences of loss of safety functions from any initiating event conceivable at the plant site c) Severe accident management issues Page 3 of 37 2 BACKGROUND The Metal Recycling Facility (MRF) operated by Studsvik UK Ltd is a small low hazard facility (1) located at Lillyhall near Workington in Cumbria. The MRF receives metallic waste items contaminated with low levels of radiological contamination from clients within the UK nuclear industry. The metallic items are processed on a batch basis that includes size reduction (if required) using conventional hot and cold cutting techniques with subsequent decontamination using industrial grit blasting equipment. All of these processes are manually operated. Following treatment all metallic items are subject to rigorous surveillance to confirm the effectiveness of the decontamination operation. The facility has no; fissile material; nuclear reactors; nuclear chemical process plant or fuel storage facilities. The MRF process is made up of a small number of Page 4 of 37
individual industrial plant items located in a single building that also contains office space and one other facility that is used for the storage of non-radiological equipment. Metallic waste delivered to the site and waiting processing is stored in approved containers external to the main process facility. 3 INITIATING EVENTS The events to be considered within this report were defined by ENSREG as Earthquakes and Flooding. These events were highlighted as risk areas following the Fukushima accident. These two subjects are discussed below with regards to the MRF. 3.1 FLOODING The MRF site is not located on the coast or near any surface water streams. Ordnance Survey maps show the site at 112 meters above sea level and approximately 3.5 km from the sea. The nearest significant surface water feature is the river Derwent approximately 4km from the site. Analysis of the Environment Agency Flood Maps has shown that the site is not in a flood warning zone from rivers or sea (2). Studsvik provided the Environment Agency with a response regarding flood and coastal risk in November 2009 (3) The Environment Agency Risk of Flooding from River and Sea Map (4) is shown below in Figure 1. This shows the MRF location (red star), local river systems (dark blue), river and coastal flooding with no defences (mid blue) and extent of flooding from extreme events (light blue). The map clearly shows that the MRF is not within a flood risk area from River or Sea. In November 2009 the Workington area suffered severe flooding (considered to be a one-in-a thousand-year event) that caused significant damage to the local infrastructure especially in Cockermouth (approximately 13km from the MRF) and Workington (approximately 6km form the MRF), the MRF site was unaffected due to the MRF location on high ground. The Studsvik assessment has considered flooding events resulting from Tsunami and rainfall as shown in Appendices 3 and 4. The assessments have not identified any requirement to change existing site arrangements or design. 3.2 EARTHQUAKE Although the UK is not located on or near any seismic boundaries it still is affected by occasional deformations caused by land uplift and squeeze from tectonic plates. Earthquakes are rare in the UK; however trends show that of these rare events the majority of earthquakes that do occur tend to be on the Western side of the British Isles (5). Using the British Geological Surveys GeoIndex Earthquake Mapping system and looking at the local area around the MRF it can be demonstrated that there have been a limited number of historic earthquakes in and around Cumbria (6). The map shown in Figure 2 below shows historic earthquakes (marked in yellow) and instrument recorded earthquakes (marked in red) and the MRF location (red star). Figure 2 Map 1 showing historic earthquakes in Northern Cumbria (scale 1:175,000) (6) Figure 1, Environment Agency Flood Risk Map for around the MRF (scale 1:40,000) (4) Page 5 of 37 1 'Reproduced with the permission of the British Geological Survey NERC. All rights Reserved' Page 6 of 37
The MRF buildings and plant items are not designed for seismic resilience however an earthquake event has been assessed as shown in Appendix 5. This assessment has not identified any requirement to change existing site arrangements or design. 3.3 OTHER EVENTS Other external natural events have been considered as part of the Studsvik assessment including wind, snowfall and extreme temperatures as shown in Appendices 6, 7 and 8 respectively. These assessments have not identified any requirements to change existing site arrangements or design. 4 CONSEQUENCES OF LOSS OF SAFETY FUNCTIONS FROM ANY INITIATING EVENT CONCEIVABLE AT THE MRF At the MRF safety is mainly related to conventional safety risks associated with an industrial engineering workshop environment together with low hazard radiological risk, resulting from contaminated metal i.e. low dose rate and low levels of contamination. There is no nuclear safety risk associated with fissile material; reactor operations or fuel storage or processing plant. As a small low hazard site there is limited dependency on off-site infrastructure. Water, gas and electrical supplies are provided to the site and the loss of these services has been considered as part of the facility assessment. As shown in Appendices 9, 10 and 11 respectively. Water is not required for any operations and is only required for drinking, washing and sanitation. Gas is only used for heating purposes. The MRF has two electrical supplies to the site SP1 supplying the production facility; and SP2 supplying the Vent Plant Room, Emergency Control Centres and Security Systems. In the event of failure, uninterruptable power supplies (UPS) in the form of battery back-ups are available to provide 300 minutes power supply to key radiological monitoring systems to allow safe evacuation of the facility. In the event of the loss of SP2 power supply there is an automatic back-up diesel generator which provides power to the site security systems and Emergency Control Centres. In the 3 years to date of construction / commissioning / active commissioning no power failures have been experienced. It is considered that the existing supplies are sufficiently robust for MRF operations and if off-site supplies were unavailable then operations could not be carried out and would be suspended until services were restored (Appendix 11). If under extreme conditions all services were lost operations would be suspended and the facility would be placed in, and remain in, a safe passive state, until services were restored. The assessments have not identified any requirements to change existing site arrangements or design. 5 SEVERE ACCIDENT MANAGEMENT ISSUES Due to the low hazard category of the MRF a severe accident scenario is not considered to be applicable. Based upon the worst case scenario considered in the facility Safety Case there is no requirement for an off-site emergency plan as required by regulation 7 of the Radiation (Emergency) Preparedness and Public Information Regulations (REPPIR) (7). On site emergency arrangements are in place and are regularly tested. Any on site emergency situation would be relatively short duration as there would be no on-going operations. Long term disruption due to external events would prevent operations from re-commencing and the requirement for site based actions over long periods of time is not considered applicable. Appropriate welfare arrangements are in place to accommodate foreseeable extended durations. It is considered that the existing emergency arrangements are satisfactory for the hazard category associated with the MRF. In the event of a site emergency all operations would cease, enabling the facility to achieve an immediate stable state Potential events occurring during a Site Emergency situation have been assessed as shown in Appendix 12. These assessments have not identified any requirements to change existing site arrangements or design. It is therefore considered that the current arrangements for emergency control, instrumentation and communications are satisfactory. 6 CONCLUSIONS An assessment of the Studsvik Metals Recycling Facility (MRF) has been carried out in accordance with the ENSREG Stress Test requirements. The assessment has not identified any requirements to change existing site arrangements or design. The MRF is a small low hazard facility that has no; fissile material; nuclear reactors; nuclear chemical process plant or fuel storage facilities. There is therefore no risk associated with criticality or fuel cooling. The MRF is located on elevated ground away from the coastline and any large water courses therefore the risk associated with the facility being flooded is very low. In the unlikely event that the area was to encounter a significant earthquake at or near the facility, site operations would stop or be suspended and the site emergency procedures implemented. Due to the low hazard nature of the site there is no requirement for an off-site emergency plan as required by regulation 7 of the Radiation (Emergency) Preparedness and Public Information Regulations (REPPIR). It is considered that the MRF has appropriate emergency procedures and contingency plans in place and that these are appropriate to the potential risks associated with the type of operations currently undertaken at the MRF site. Page 7 of 37 Page 8 of 37
7 REFERENCES 1. Metals Recycling Facility Combined Preliminary Safety Report/Pre Construction Safety Report; February 2007 2. Metals Recycling Facility Environmental Statement; 22 nd January 2007 3. Letter date 19 th November 2009 from M McMullen to M Scott (Environment Agency) 4. Environment Agency, Risk of Flooding from Rivers and Sea Map, http://maps.environment-agency.gov.uk/wiyby/ Cited 14/12/11 5. British Geological Survey (BGS), Website, http://www.earthquakes.bgs.ac.uk/earthquakes/ukseismic.html Cited 14/12/11 6. British Geological Survey, GeoIndex Onshore Mapping, Website, http://maps.bgs.ac.uk/geoindex/default.aspx Cited 14/12/11 7. UK Metal Recycling Facility REPPIR 2001 Reports of Assessment; May 2011 APPENDICES APPENDIX 1 ENSREG STRESS TESTS Page 9 of 37 Page 10 of 37
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APPENDIX 2 ONR LETTER Page 25 of 37 Page 26 of 37
APPENDIX 3 - CONSIDERED EFFECTS ON THE MRF FOLLOWING A TSUNAMI Page 27 of 37 Page 28 of 37
APPENDIX 4 CONSIDERED EFFECTS ON THE MRF FOLLOWING A FLOOD APPENDIX 5 CONSIDERED EFFECTS ON THE MRF FOLLOWING AN EARTHQUAKE Page 29 of 37 Page 30 of 37
APPENDIX 6 CONSIDERED EFFECTS ON THE MRF FOLLOWING HIGH WINDS APPENDIX 7 CONSIDERED EFFECTS ON THE MRF FOLLOWING SEVERE SNOWFALL Page 31 of 37 Page 32 of 37
APPENDIX 8 CONSIDERED EFFECTS ON THE MRF FOLLOWING EXTREME TEMPERATURES APPENDIX 9 CONSIDERED EFFECTS ON THE MRF FOLLOWING LOSS OF WATER Page 33 of 37 Page 34 of 37
APPENDIX 10 CONSIDERED EFFECTS ON THE MRF FOLLOWING LOSS OF GAS APPENDIX 11 CONSIDERED EFFECTS ON THE MRF FOLLOWING LOSS OF POWER Page 35 of 37 Page 36 of 37
APPENDIX 12 CONSIDERED EFFECTS ON THE MRF DURING SITE EMERGENCY Page 37 of 37