A structured and systematic approach to hazard identification is fundamental to any safety assessment. Using a comprehensive underpinning hazard identification exercise, it is possible to demonstrate that hazard analysis is complete, that suitable and sufficient safety measures have been identified and that levels of risk are fully understood. A Hazard and Operability Study (HAZOP) provides that structured vehicle.
TÜV SÜD Nuclear Technologies personnel fully understand the requirements of a HAZOP and are experienced in the conduct and application of the common techniques available. These include:
Provision of Chairman and/or secretary to formal HAZOP studies either as single stand-alone exercises or within the context of a broader project to justify the safety of a particular plant or process. Our personnel have experience of all levels of HAZOP 0, I and II
Conduct plant walk downs and participation in formal desktop studies identifying hazards in consultation with plant personnel or designers
Performing Human Factors Task Analyses considering either existing or proposed new activities
Having conducted a hazard identification exercise our safety consultants are also experienced in the derivation of fault schedules flowing from those exercises.
The production of Modern Safety Cases, whether for new or existing facilities, requires input from a range of disciplines:
Operators/owners to specify the functionality required of the plant, process or equipment to be considered
Nuclear safety assessors assess the hazards associated with the intended process and identify those specific requirements imposed upon the equipment in order to deliver the required safety functionality
Engineers/designers provide evidence, as required, demonstrating that those requirements can be met
All parties collaborate and interact as required to ensure that these related requirements are all met to the greatest degree achievable. Where necessary, any shortcomings or differences are reconciled through formal application of the ALARP principles
For the Safety Case to be constructed successfully it is essential for the interfaces between these different groups to be managed effectively.
TÜV SÜD Nuclear Technologies have experienced safety case consultants with a full understanding of the engineering requirements of a Modern Standards Safety Report. Our staff are able to manage the production of the safety case and interactions with engineers/designers.
TÜV SÜD Nuclear Technologies has staff capable of compiling all elements that make up a Safety Case and the supporting assessments:
Fault Schedule and Fault Sequence Analysis
Design Basis Analysis
Probabilistic Safety Assessment
Safety Functional Requirements
Safety Management Arrangements
Safe Operating Envelope
The Company is structured into complimentary groups covering Radioactive Waste and Environmental Management, Safety and Radiation Physics and Decommissioning and Engineering that allow for complete and thorough management of safety case production, and its successful delivery.
Having established a comprehensive list of hazards arising from either normal operations or potential fault sequences it is necessary to specify suitable and sufficient measures to ensure that the risk associated with those hazards is managed. Following current best practice, as enshrined in the NII Safety Assessment Principles, this assessment incorporates both Design Basis (primarily qualitative) Assessment and Probabilistic (primarily quantitative) Assessment.
All such assessment requires an evaluation of the degree of harm that may be associated with a given hazard should it be realised.
TÜV SÜD Nuclear Technologies personnel are familiar with the assessment methodologies employed by all UK Nuclear Site Licensees and understand both when and how these methods may be deployed. Our staff are able to identify and evaluate the effectiveness of available safety measures providing input to designers or substantiation engineers as necessary with regard to performance requirements for those measures within the context of the particular operation or activity considered.
TÜV SÜD Nuclear Technologies personnel are able to evaluate the reliability of particular systems or components (including human reliability assessment) utilising standard statistical techniques and utilise that output in Fault and Event Tree analyses as appropriate in order to derive quantified risk estimates for comparison against specified criteria.
The principle of As Low As Reasonably Practicable (ALARP) is captured within the heart of the regulatory regime under which all hazardous activities undertaken within the UK are governed. In practice the concept of ‘Reasonable Practicability’ is widely interpreted to mean that any operator must consider and implement all available measures to minimise risk unless the cost associated with the benefit derived from that measure (in terms of time, effort and money) can be shown to be grossly disproportionate to the level of risk averted.
TÜV SÜD Nuclear Technologies personnel are experienced in the application of ALARP at all stages of development of a plant or process and in demonstrating whether an ALARP solution has been derived.
This includes explicit identification of possible adjustments to existing operational practices and the specification of engineered safety measures within system designs. Nuclear Technologies personnel are also familiar with the process of reconciling recommendations arising from safety analysis or engineering substantiation against the ongoing needs of the operational plant which can include the development of justification for the full or partial rejection of recommendations on the grounds of gross disproportionality.
TÜV SÜD Nuclear Technologies apply the principle of ALARP in all support to clients. More specifically we have recently supported Sellafield Ltd in understanding their dependence on man entries and use of air-fed suits in undertaking decommissioning within alpha environments (plutonium facilities). One of our deliverables was a software based toolkit, which assists the decommissioning practitioner to identify the ALARP approach to any alpha (plutonium facility) decommissioning challenge. The toolkit and its methodology were commended by the Nuclear Installations Inspectorate (NII).
Nuclear criticality safety ensures that an inadvertent, self-sustaining nuclear chain reaction cannot occur for operations involving fissile isotopes. More than 60 criticality accidents have occurred since the advent of nuclear engineering over 60 years ago, and of these a large proportion occurred in process facilities. A criticality accident has the potential to deliver a sudden and potentially lethal dose of radiation and, in some cases the nuclear reaction will not shut down, potentially requiring further human intervention which can create further risk of a substantial dose uptake. Fortunately as the general safety of nuclear material processing has developed, criticality safety has evolved alongside it. Of the 22 known criticality accidents associated with process facilities only 2 have occurred in the last 30 years.
TÜV SÜD Nuclear Technologies has developed a track record in criticality safety assessment while supporting many key clients in the nuclear industry.
Our consultants can work on secondment to the client on a full or part time basis as well as working on standalone projects from their own offices. Our personnel are active members of the UK Criticality forum which meets to discuss criticality safety methodology issues and are encouraged to contribute to further criticality safety knowledge. Notable project experience includes:
Criticality safety assessment of existing operations involving fissile material on several licensed sites;
Experience using both MONK and MCNP modelling codes for the assessment of fissile system neutronics;
Authoring of criticality safety cases for the transport of fissile material in the UK, both on and off site;
Criticality safety input into all phases of design and build of new facilities;
Authoring of CIDAS omission documentation for new and existing facilities;
Peer review of criticality safety cases and assessments.
Exposure to high levels of ionising radiation can present a significant safety risk. Radiation shielding is a specialist technical discipline; the aim of which is to develop engineered solutions to reducing external radiation exposure to personnel and the public. Radiation physics specialists create detailed computer models and use analytical techniques to simulate interactions of radiation in matter.
TÜV SÜD Nuclear Technologies has a dedicated team of radiation physicists specialising in shielding and dose uptake. The team has considerable experience in providing shielding and dose uptake support to the nuclear, defence, medical and research sectors including:
- Civil Nuclear Industry
- Nuclear Transport
- Defence Nuclear
- European High-Energy & Fusion Research
- Medical LINACS
We can deliver an unequalled variety of expertise in high quality shielding design advice to clients within UK, European and International regulatory frame works. Nuclear Technologies can provide shielding support from plant conception right through to continued operation support, plant modifications and decommissioning and can provide the required documentation to support facility safety cases.
In addition to shielding and dose uptake assessment, our expertise also encompasses activation analysis and CIDAS detector placement assessments. Nuclear Technologies helped pioneer the technique of using the powerful adjoint calculation mode in Attila in CIDAS detector placement assessments.
Our consultants are suitably experienced and qualified to use the latest advanced computational codes on purpose-built, multi-core servers to provide detailed and efficient assessment of radiation shielding problems. This includes both stochastic and deterministic codes as follows:
- ORIGEN ARP
Our consultants are also experienced in using shielding codes from the ANSWERS suite, including MCBEND, RANKERN and FISPIN. Furthermore, they are well versed in radiation transport principles and the use of analytical methods to quickly scope and check calculations made by the above sophisticated analysis techniques.
In summary, the TÜV SÜD Nuclear Technologies Shielding Team can:
Add value to a contract by applying both a wealth and depth of experience
Develop a rapport with clients to develop effective and practicable shielding solutions
Perform detailed shielding calculations using shielding codes and/or analytical techniques
Provide generic design advice and bespoke shielding design solutions
Complete deliverables at a competitive price utilising intelligent and flexible employment of graded consultants
Peer Review/Independent Nuclear Safety Assessment (INSA) is required prior to a safety case being submitted to a regulator and is the vehicle by which any submission is subjected to independent scrutiny.
The purpose of the assessment is to verify that a robust and sustainable safety case has been made, with no safety significant issues overlooked. Assessors are chosen on the basis that they would be capable of producing the work under review. They require significant knowledge and experience of safety case construction, in depth technical knowledge and experience of the technical specialism associated with the subject under review, and previous experience of carrying out INSA or peer review.
The INSA review process follows a rigorous and structured process with relevant findings, omissions and recommendations fed back to the project for close out.
TÜV SÜD Nuclear Technologies personnel are well placed to undertake INSA/peer review work as we have worked on all 29 nuclear sites in the UK. Many sites have analogous challenges and there is opportunity to apply our knowledge and vast experience to these reviews. We are able to bring our knowledge of safety case and equipment design shortfalls that may have been unknown to designers.
We are able to construct INSA teams comprising personnel with extensive safety assessor experience and INSA experience, combined with experts who have detailed and working knowledge of the specific subject areas. Many of our more experienced experts will have a decade or more experience of a particular subject, through previous employment on nuclear licensed sites. We are careful to select the most appropriate and experienced team to meet the exact requirements of any review.
In addition, TÜV SÜD Nuclear Technologies experts have been called upon by many Nuclear Site Licensees and operators to both lead and contribute to many such reviews both as independent projects and as independent members of safety panels required to validate assessments performed under the conditions of the applicable Site Licence.
TÜV SÜD Nuclear Technologies have held an INSA framework to provide services to Sellafield Ltd since 2005. We have a number of consultants who previously served on the Sellafield site in a range of senior capacities whom we are able to select for any particular review.
Within any Safety Case, there is a requirement to demonstrate that any and all engineered structures, systems or components (SSCs) claimed as contributing to the achievement of safe operation are able to deliver those roles throughout the lifetime of that Safety Case. The process of Engineering Substantiation is applied to SSCs within existing facilities and commonly involves plant walkdowns, review of operational history, confirmation of maintenance practices and a review of the SSC design against applicable, current, engineering standards. Design substantiation is an equivalent process applied to all new SSCs.
The precise scope of the substantiation exercise varies depending upon the safety significance of the role delivered. Where appropriate, recommendations are made for the rectification of any shortfalls against the specified performance requirements and passed forward for formal ALARP consideration.
Our staff have experience in providing engineering and design substantiation in support of design justification, safety case development and option studies.
In support of the periodic safety reviews we are able to provide individual resources or multidisciplinary teams to complete engineering substantiation activities.
Our personnel can also act as independent peer reviewers and “intelligent customer”, liaising with facility users, stakeholders and internal and external design houses.
We also substantiate the need for placement of Criticality Incident Detection Systems (CIDS) and substantiate the safety function of Safety Related Equipment (SRE) specifically associated with criticality protection and shielding.