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  • Planning Act 2008 The Infrastructure Planning (Applications: Prescribed Forms and Procedure) Regulations 2009

    The Port Talbot Steelworks (Power Generation Enhancement) Order

    MAH1.01 - High Level Assessment of Major Accident Hazards

    PINS Reference EN010062

    Document No. MAH1.01

    Author Pinsent Masons

    Revision Date Description

    0 April 2015 Submission Version

  • The Port Talbot Steelworks (Power Generation Enhancement) Order High Level Assessment of Major Accident Hazards MAH1.01

    April 2015 2

    Contents 1. Introduction .............................................................................................. 3 2. Executive Summary ................................................................................. 5 3. Review of Major Hazards ......................................................................... 6 4. Major Loss of Containment of Fuel Gas ................................................ 7 5. Conclusions ........................................................................................... 11

    Appendices: Appendix 1 - Process Risk Assessment Process

    Appendix 2 - Calculations

    Appendix 3 - DNV-GL ‘Corus Technical Note’

    Appendix 4 - Port Talbot Steelworks Safety Report 2013

  • The Port Talbot Steelworks (Power Generation Enhancement) Order High Level Assessment of Major Accident Hazards MAH1.01

    April 2015 3

    1. Introduction

    1.1 This report has been written in support of an application by Tata Steel UK Limited ("Tata") under the Planning Act 2008 for a development consent order ("DCO") to construct, operate and maintain a process gas-fired power generating station ("the Proposed Development") within the Port Talbot Steelworks at Port Talbot, South Wales ("the Application").

    1.2 The report contains a high-level assessment of the extent and severity of known major hazards at the Proposed Development with the potential to impact on the existing steelworks installation and the local population.

    1.3 As a result of the presence of 'hazardous substances'1 at installations within the Port Talbot steelworks site, the site is a ‘Control of Major Accident Hazards (COMAH) Tier 1’ site. Tata is therefore obliged to hold and maintain a 'safety report' for the site under the terms of the Control of Major Accident Hazards Regulations 1999 ("the COMAH Regulations").

    1.4 Although the Proposed Development would not itself be a COMAH site for the purposes of the COMAH Regulations, it would be situated within the formal 'consultation zone' of the steelworks which is a regulated 'establishment'2. When new facts arise or modifications take place within a regulated establishment, the safety report for that site may need to be reviewed under the terms of regulation 8 of the COMAH Regulations.

    1.5 As no additional qualifying inventories of COMAH substances will be present at the Proposed Development, Tata currently considers that the current ‘2013 COMAH Safety Report’ for the steelworks site will not need updating. Instead, the presence of the Proposed Development will be reflected in the ‘2018 Port Talbot COMAH Safety Report’. Final decisions in relation to the COMAH Safety Report will be taken once more information becomes available on the design of the Proposed Development. This approach has been verbally agreed with Tata's Principal HSE Inspector, Mr Alan Strawbridge.

    1.6 Tata has adopted a six stage risk assessment process to review health and safety risks within the consultation zone of the Port Talbot Steelworks COMAH site. The stages in this process are set out in detail in the ‘2013 Port Talbot Safety Report’, an extract of which outlining these phases is enclosed at Appendix 1 to this report.

    1 As defined in regulation 2 of the Control of Major Accident Hazards Regulations 1999 2 As defined in regulation 2 of the COMAH Regulations.

  • The Port Talbot Steelworks (Power Generation Enhancement) Order High Level Assessment of Major Accident Hazards MAH1.01

    April 2015 4

    1.7 Tata's Process Safety Department (part of the Health, Safety and Environmental Department) has carried out a high-level, initial assessment of the potential for increased risk to health and safety at the Port Talbot Steelworks as a result of the Proposed Development. This initial review forms part of the existing six-stage framework. The Proposed Development has passed the first (HS1) stage of this package of risk assessments and the findings of that initial assessment are set out in this report, the "HS1 Stage 'High Level' Risk Assessment".

    1.8 The Proposed Development will in due course be assessed at the HS2 stage, when more detailed information is available about the detailed design. The HS2 stage will result in a more granular and detailed risk assessment. Both HS1 and HS2 stages are in the ‘Inherently Safe Design’ phase where actions and recommendations focus on eliminating, reducing, replacing or simplifying the threats and sources of hazards.

    1.9 As the design progresses, a more detailed set of Process Hazard Review and Risk Assessments (HS3) will be carried out to ensure that the risks are controlled to ‘As Low As Reasonably Practicable’ (ALARP). Where ‘Major Accident Hazards’ are identified, ‘Layer of Protection Analysis’ (LOPA) studies will be carried out to ensure that the causative mechanisms are credible, that the safeguards claimed are documented, any improvements recommended from the risk assessments captured and an ALARP demonstration made.

    1.10 As stated above, it has been agreed with Tata's Principal HSE Inspector that the current ‘2013 COMAH Safety Report’ will not need updating at present. Tata will, however, continue to complete the six-stage assessment process in respect of the Proposed Development and will keep the HSE informed of any change in assumptions, risks or proposed approach.

  • The Port Talbot Steelworks (Power Generation Enhancement) Order High Level Assessment of Major Accident Hazards MAH1.01

    April 2015 5

    2. Executive Summary

    2.1 This assessment identifies that the only possible, known major hazard from the Proposed Development is the potential for major loss of containment fuel gas from inside the power generation plant building due to a guillotine of gas pipework and a subsequent escape of fuel gas from the power generation plant building. Such an escape would have the potential to impact both the wider Port Talbot Steelworks site and the local community, most especially those in Tiabach.

    2.2 This assessment concludes that such an escape is a barely credible threat and, in the unlikely event that it did occur, a number of controls would be in place to limit the duration of any such release and therefore the risk to the public. The assessment further finds that, even if the control measures failed to prevent or mitigate a catastrophic release of fuel gas, the Proposed Development poses no additional ‘Major Accident Hazard’ to on-site or off-site populations. In other words, the presence of the Proposed Development would not increase the risk from the rest of the steelworks site.

    2.3 The information contained in this report is intended to demonstrate the suitability of the site for the Proposed Development and show that Tata has adequately considered the impact of known hazards from the Proposed Development to the public. Potential risks will continue to be considered as the design of the Proposed Development is progressed to ensure that any such risks are adequately managed and controlled through the design, site safety procedures and through Tata's on- going obligations under the COMAH Regulations.

  • The Port Talbot Steelworks (Power Generation Enhancement) Order High Level Assessment of Major Accident Hazards MAH1.01

    April 2015 6

    3. Review of Major Hazards

    3.1 An assessment of the existing risks on the Port Talbot is given in the Port Talbot 2013 COMAH Safety Report', which is appended to this report.

    3.2 The Proposed Development comprises only a very small addition to the existing inventory of hazardous substances on the Port Talbot Site. The only hazardous substance affected by the Proposed Development is the blast furnace gas (BFG), the volume of which will increase by only around 100m³ (of a current total volume of around 100,000m³). In addition, although the existing pipe work carrying the BFG will be extended slightly to accommodate the Proposed Development, the location of the hazardous substances within the site is not considered to change in any significant way, and in particular the BFG will not be brought significantly closer to the boundary of the site within these new pipes. The risk of known major hazards across the Port Talbot COMAH site is therefore not considered to increase to the extent that the current safety report needs to be reviewed. This conclusion has been discussed with Tata's HSE Principal Inspector and will be kept under continual review as the assessment progresses through Tata's 6 stage process.

    3.3 Tata has concluded that the only new or different major hazard that could potentially arise from the Proposed Development is the possibility for major loss of containment of fuel gas from inside the power generation plant building of the Proposed Development and a subsequent escape of gas from that building. The potential consequences of such an incid

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