Tails Management Facility, Urenco UK Limited, Capenhurst

Transcription

1 Title of document Tails Management Facility, Urenco UK Limited, Capenhurst Acknowledgement of Hydrogen Fluoride Processing and Storage Facility and Cylinder Handling Facility safety cases for Tails Management Facility on the Urenco UK Limited Capenhurst Licensed Site Project Assessment Report ONR-DFW-PAR Revision 2 2 September 2014 Template Ref: ONR-DOC-TEMP-005 Revision 8 Page 1 of 13

2 Office for Nuclear Regulation, 2014 If you wish to reuse this information visit for details. Published 08/14 For published documents, the electronic copy on the ONR website remains the most current publicly available version and copying or printing renders this document uncontrolled. Office for Nuclear Regulation Page 2 of 13

3 EXECUTIVE SUMMARY Title Request to acknowledge receipt of the Pre-Commencement Safety Reports for the Cylinder Handling and Hydrogen Fluoride Processing and Storage Facilities that are being constructed on the Capenhurst Licensed Site as part of the Tails Management Facility. Permission Requested Urenco UK Limited has requested, in accordance with its arrangements made under Licence Condition 19, acknowledgement of receipt of the Cylinder Handling Facility (CHF) and the Hydrogen Fluoride (HF) Processing and Storage Facility safety cases. These safety cases will permit the commencement of mechanical, electrical and instrumentation (ME&I) installation within part of the Tails Management Facility (TMF), which is being constructed on the Urenco UK Limited Capenhurst licensed site. Background The Licensee s objective, in constructing the CHF and HF processing facilities as part of the overall TMF, is to enable the conversion of depleted Uranium Hexafluoride Tails (Hex Tails), which is currently stored on the Capenhurst site, into the more stable Uranium Octaoxide and Hydrogen Fluoride (which is to be sold). This conversion process will reduce the overall risk on the site associated with the accidental release of Uranium Hexafluoride gas. Both safety cases have been categorised by the licensee as safety category A on the basis that there are identified faults with off-site consequences in excess of 1mSv or significant chemotoxic consequence. There are six safety cases in total associated with the ME&I installation within the Tails Management Facility. Assessment and inspection work carried out by ONR in consideration of this request In support of this acknowledgement, the Office for Nuclear Regulation has completed an initial assessment of the Pre Commencement Safety Reports and has made a number of visits to the licensed site to discuss the safety cases in more detail. Matters arising from ONR's work ONR has decided not to conduct an assessment of these two safety cases at this stage in the context of the wider safety case submissions for ME&I installation for the Tails Management Facility. ONR has decided to focus its assessment resource onto the safety cases associated with the vapourisation and deconversion facilities within the TMF on the basis that these facilities are associated with both significant radiological and chemotoxic faults as well as the introduction of novel technical processes. In addition, there remain outstanding a number of associated Engineering Substantiation Reports (ESRs) associated with the CHF and HF facilities. ONR has judged that these Office for Nuclear Regulation Page 3 of 13

4 omissions would prevent an accurate regulatory judgement being made as to the adequacy of the safety cases at this time. Conclusions The Office for Nuclear Regulation concludes that it does not intend to formally examine the safety cases associated with both the CHF and HF facilities at this stage. Recommendation Licence Instruments 534 and 535 will be issued to acknowledge receipt of the Pre- Commencement Safety Reports associated with the HF Processing and CHF facilities respectively. These will notify the licensee that the Office for Nuclear Regulation does not intend to examine the safety documentation at this stage, but will examine the Pre Active Commissioning Safety Reports (PACSR), which represents the next phase of the TMF. The Office for Nuclear Regulation anticipates issuing subsequent Licence Instruments associated with other facilities within the TMF, and intends to send a separate letter to the licensee informing them of its concern regarding the development and submission of safety cases without accompanying ESRs, and that ONR requires these issues to have been completely resolved prior to any request for active commissioning. Office for Nuclear Regulation Page 4 of 13

5 LIST OF ABBREVIATIONS ALARP BSL BSO CHF HOW2 HSE HID NDA ONR PACSR PCSR PSA PSR RGP SAP SFAIRP SSC TAG TMF UCP UUK As low as reasonably practicable Basic Safety level (in SAPs) Basic Safety Objective (in SAPs) Cylinder Handling Facility (part of the TMF) (Office for Nuclear Regulation) Business Management System The Health and Safety Executive Hazardous Installations Directorate Nuclear Decommissioning Authority Office for Nuclear Regulation Pre-Active Commissioning Safety Report Pre-commencement Safety Report (in the context of UUK arrangements) Probabilistic Safety Assessment Preliminary Safety Report Relevant Good Practice Safety Assessment Principle(s) (HSE) So far as is reasonably practicable System, Structure and Component (ONR) Technical Assessment Guide Tails Management Facility Urenco ChemPlants Limited Urenco UK Limited Office for Nuclear Regulation Page 5 of 13

6 TABLE OF CONTENTS 1 PERMISSION REQUESTED BACKGROUND ASSESSMENT AND INSPECTION WORK CARRIED OUT BY ONR IN CONSIDERATION OF THIS REQUEST MATTERS ARISING FROM ONR S WORK CONCLUSIONS RECOMMENDATIONS REFERENCES (To update Table of Contents, right click on contents, Update Field, Update Entire Table) Office for Nuclear Regulation Page 6 of 13

7 1 PERMISSION REQUESTED 1. Urenco UK Limited has requested (References 6 and 7), in accordance with its arrangements made under Licence Condition 19, acknowledgement of receipt for two nuclear safety cases : - Tails Management Facility Hydrogen Fluoride Processing and Storage Facility Category A Pre-Commencement Safety Report, UUK Revision 9 dated 8 April 2014; - Tails Management Facility Cylinder Handling Facility Category A Pre- Commencement Safety Report, UUK Revision 8 dated 10 January In addition, the licensee has supplied the minutes of UUK Limited Nuclear Safety Committee (Reference 8). 3. This Project Assessment Report has been written to support a recommendation to issue a Licence Instrument to acknowledge receipt of these two nuclear safety cases. 2 BACKGROUND 4. The Tails Management Facility (TMF) is being constructed and will be operated by Urenco ChemPlants Limited (UCP), which is a tenant on the UUK licensed site. The TMF will convert depleted UF 6 (Hex) Tails to tri-uranium octaoxide (U 3 O 8 ) and Hydrogen Fluoride (HF). The TMF comprises six interacting facilities to receive full cylinders of UF 6, to decontaminate and maintain the facilities and treat the solid and liquid arisings as follows : - Cylinder Handling Facility (CHF), which will permit the receipt, despatch and safe storage of the Type 48 Uranium Hexafluoride (UF 6 ) transport cylinders - Residue Recovery Facility (RRF) and Cylinder Wash Facility (CWF), which will receive and treat solid and liquid arisings from the entire TMF. The facility will separate out recyclable material and immobilise or condition all other materials for authorised disposal or long term storage. - Decontamination and Maintenance Facility (DMF) which will provide maintenance for all TMF Facilities and associated radiological and chemical decontamination of plant items. - Vapourisation and Deconversion Facilities the main component of the TMF, where depleted UF 6 is vapourised and deconverted in a kiln to U 3 O 8. - Uranium Oxide Store (UOS) which will receive and store the U 3 O 8 in a painted mild steel DV70 containers. The UOS is intended to provide long term safe storage of the full DV70 containers. Hex Tails that are received for processing from Urenco facilities in Germany or the Netherlands will be returned to those countries as U 3 O The Licensee had previously submitted a different variant of the TMF PCSRs in 2009 (TRIM Folder ), and these were assessed by ONR (Reference 9)) and subsequently agreements were issued by means of a series of Licence Instruments (Reference 10). ONR informed the licensee (Reference 11) that in many cases the actual detail associated with the design was incomplete, and informed the licensee that if any changes in design were later required for regulatory reasons prior to active commissioning and are resisted on ALARP grounds, then costs associated with Office for Nuclear Regulation Page 7 of 13

8 equipment removal, improvements or replacement would not count to the sacrificial component in the ALARP case. Construction of the TMF has proceeded on that basis. 6. The assessment of the CHF component of the TMF was completed in 2010 (Reference 12) and concluded that although the basic principles were met at that early stage in the design, there were elements of detail missing associated with criticality safety and whole body/extremity dose accrual resultant from operations. At this stage, these items still remain outstanding. 7. The main components of the TMF are the vaporisation and deconversion facilities, which will transform the solid UF 6 into the gaseous phase and subsequently add gaseous reagents in a kiln to produce solid U 3 O 8 and large quantities of liquid HF, which is to be exported for reuse in other non nuclear industry. ONR has decided to focus its assessment of the TMF safety documentation at this stage on these two plants, and conduct a more comprehensive assessment of the CHF and HF facilities prior to active commissioning. 8. As part of the movement of material through TMF, full and empty heeled 48Y cylinders are handled and stored within a Cylinder Storage Facility (CHF). The HF Processing Plant will collect and treat the liquid and gaseous HF streams produced from the deconversion facilities. Aqueous HF from the deconversion facilities will be mixed with HF recovered from the kiln gases these gases are subsequently scrubbed and washed prior to discharge to atmosphere in accordance with an EA permit. 9. The HF facility also comprises storage to permit temporary storage on site prior to export by road tanker for use commercially off-site. The facility accommodates additional plant for neutralisation of residual HF prior to export from the plant. 10. There are no significant radiological faults that have been identified as part of HF plant operations, and the PCSR has been categorised as A resulting from assessed chemotoxic faults as required by the licensee s arrangements (Reference 13). 11. The CHF is the facility for the receipt, safe storage and despatch of Type 48Y transport cylinders within the TMF. Full cylinders entering the CHF will be transferred for processing into the TMF vaporisation facility. The notionally empty cylinders will still contain a small amount of hex tails, which is termed a heel. These heeled cylinders return to the CHF shielded heeled cylinders store for decay storage to ensure the radiological protection of the workforce. Such cylinders are subsequently washed in the CWF. 12. The radiological faults associated with the operation of the CHF are associated with varying degrees of loss of cylinder containment with subsequent release of gaseous UF 6. The estimated public consequence following this fault is assessed by the licensee as being between 1mSv and 5mSv and therefore the CHF PCSR has been categorised as A. 13. The TMF will become a top tier COMAH site following operations, and the licensee has submitted a COMAH PCSR to HSE HID on behalf on ONR and EA as the joint competent authority. Assessment of this COMAH PCSR (Reference 14) has identified a number of shortfalls associated with the ALARP assessment and HID have notified UCP that these will require rectification before the next stage in the COMAH assessment. 3 ASSESSMENT AND INSPECTION WORK CARRIED OUT BY ONR IN CONSIDERATION OF THIS REQUEST Office for Nuclear Regulation Page 8 of 13

9 14. Hazards within the HF processing facility and ancillary plant are dominated by chemotoxic faults associated with the release of HF with minimal radiological consequence. The design, operations and chemical faults associated with this facility have been assessed by HSE HID as part of the initial PCSR submitted under COMAH (Reference 14). HID concluded that although no fundamental issues were raised, the TMF COMAH submission lacked sufficient detail in many areas such that a conclusion could not be reached. Therefore HID intend to place greater emphasis on the adequacy of the COMAH POSR which is to be submitted to HID prior to the start of active commissioning (and therefore will coincide with submission to ONR of the PACSR). 15. ONR has completed a number of targeted interventions in support of the TMF assessment, including on LC19, 20 and 21 arrangements (Reference 15), supported by routine regulatory interactions including 3 monthly updates on TMF progress, most recently in July 2014 (References 16 and 17). 16. ONR decided in 2013, noting that many aspects of the design of the TMF were not completed, to complete a sampling based assessment of the TMF at the PCSR stage with the objective of gaining sufficient regulatory confidence that: - There were no fundamental regulatory objections to the generic operation of the TMF, particularly associated with the novel aspects of the process, - That the SAPs were likely to be satisfied. 17. There remain elements of design details associated with criticality in particularly, as identified in the ONR assessment completed in The TMF CIDAS submission document had been submitted in 2013 by UCP to the UUK LC13 NSEC where it was rejected. ONR has therefore concluded that would be limited value in any further assessment at this stage, noting that the construction and ME&I installation is proceeding at some commercial risk and to focus its assessment resources in establishing that ONR would have no fundamental objection to the operation of the vapourisation and deconversion facilities. 18. On that basis, ONR decided to focus its assessment at this stage on the deconversion and vapourisation facilities, and specifically not to examine the CHF or HF PCSRs at this stage, but to await the submission of the PACSR at which time all remaining design and safety arguments will be complete. 4 MATTERS ARISING FROM ONR S WORK 19. The CHF safety documentation remains incomplete in that there are more than 15 outstanding safety related actions required to be completed before active commissioning can commence i.e. to be resolved at the Pre Active Commissioning Safety Report (PACSR) stage. The criticality safety argument relies on a TMF generic CIDAS omission case, which was not accepted by the UUK NSEC and remains outstanding. Although the licensee has submitted the PCSR for the CHF, the associated underpinning ESRs have not been completed and remain ongoing. 20. There remain issues outstanding from ONR s assessment of the CHF PCSR in 2011 (Reference 11) associated primarily with criticality and elements of detailed plant design. ONR has concluded that these issues largely remain outstanding. 21. There are no radiological faults identified in the HF Processing and Storage PCSR. HSE HID have completed an assessment of the TMF COMAH PCSR (Reference 14) and have concluded that it is not complaint with the requirements of Regulation 7(1) of COMAH in that a suitable and sufficient ALARP demonstration of the TMF has not Office for Nuclear Regulation Page 9 of 13

10 been made. HSE HID have therefore issued a letter (Reference 14) to UCP on that basis, requiring full resolution of the identified deficiencies at the COMAH POSR stage, which is prior to the introduction of COMAH quantity materials, which is coincident with the start of active commissioning and the submission to ONR of the accompanying PACSRs. HSE HID, the EA and ONR have worked closely during this assessment to share regulatory intelligence and to minimise the overall regulatory burden on the licensee. 22. The licensee, UUK Limited, is a mature organisation and has a generally good operational safety track record. ONR has decided to complete a sampling based assessment of the TMF safety documentation at this stage, and to complete a more detailed assessment prior to active commissioning in As part of this sampling ONR has focussed on the deconversion and vapourisation safety cases, and has decided not to examine the CHF or HF safety cases. The basis for this judgement is that there remain a number of significant outstanding issues identified within both PCSRs that would prevent a meaningful regulatory judgement being made. 5 CONCLUSIONS 23. The issues associated with the CHF identified by ONR in its 2011 assessment of the PCSRs remain outstanding, and in this sense, the benefit of further ONR assessment at this stage would be minimal. There are minimal radiological consequences associated with the HF Facility, and therefore ONR has committed its limited assessment resource in a proportionate manner in examining the deconversion and vapourisation PCSRs. The objective of this approach is to both confirm that there are no regulatory blockers to the final operation of the TMF and to conduct a number of deep slices to affirm that the TMF safety cases will be compliant with the SAPs. 24. This report presents evidence to support the conclusion that ONR should not examine the CHF or HF PCSRs at this stage, but that ONR does intend to examine the PACSRs. This will be communicated to the licensee in letters references 18 and 19 supporting the two Licence Instruments 534 and RECOMMENDATIONS 25. The project assessment report recommends that ONR issue two acknowledgement Licence Instruments Numbers 534 and 535 indicating the ONR does not intend to examine the CHF and HF PCSRs at this stage, but that ONR does intend to examine the two corresponding PACSR safety cases. Office for Nuclear Regulation Page 10 of 13

11 7 REFERENCES 1. ONR How2 Business Management System. Purpose and Scope of Permissioning. PI/FWD Issue 3. HSE. August Safety Assessment Principles for Nuclear Facilities Edition Revision 1. HSE. January TAGs list under one reference, give hyperlink to top level table on web-site only, e.g. Structural Integrity Civil Engineering Aspects. NS-TAST-GD-017 Revision 3, May External Hazards. T/AST/013 Issue 3. HSE. April Western European Nuclear Regulators Association. Reactor Harmonization Group. WENRA Reactor Reference Safety Levels. WENRA. January IAEA guidance list under one reference, give hyperlink to top level table on web-site only, e.g. Safety of Nuclear Power Plants: Design. Safety Requirements. International Atomic Energy Agency (IAEA). Safety Standards Series No. NS-R-1. IAEA. Vienna Letter from Urenco UK Limited requesting acknowledgement of Tails Management Facility Hydrogen Fluoride Processing and Storage Pre Commencement Safety Report, No. UUK , Revision 9 dated 8 April TRIM 2014/ Letter from Urenco UK Limited requesting acknowledgement of Tails Management Facility Cylinder Handling Pre Commencement Safety Report, No. UUK , Revision 8 dated 16 October TRIM 2014/ Urenco LC13 NSEC meeting minutes 2014 TRIM 2014 (16039, 16029, 16014, 16010) 9. ONR Assessment of 2009 submissions of Tails Management Facility Pre-Construction Safety Reports TRIM , and Licence Instruments for ONR Assessments in Reference 9 TRIM 2010/341682, and Letter from ONR to UUK noting commercial risk and lack of some design clarity, ALARP argument restrictions if changes are required in design TRIM 2011/ ONR Assessment of TMF Cylinder Handling Facility PCSR 2010/ Extracts from UUK Safety Assessment Handbook (LC14) in COMAH Assessment papers completed by HSE HID in COIN SVC and ONR LC19/20/21 inspection of UUK arrangements, Intervention Report 2013/ UUK Annual Review of Safety 2013/4, Contact Report 2014/ Office for Nuclear Regulation Page 11 of 13

12 17. Tails Management Facility Regulatory Update Meeting June 2014, Contact Report 2014/ Letter from ONR to UUK Limited, Licence Instrument 534, TRIM 2014/ Letter from ONR to UUK Limited, Licence Instrument 535, TRIM 2014/ Office for Nuclear Regulation Page 12 of 13

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