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Atkins: world-class engineering

Atkins is one of the largest engineering consultancies in the world with more than 17,000 staff operating across the globe, including more than 3,500 staff in the United States and 1,500 staff involved in nuclear projects in Europe, USA and the Middle East. We plan, design, and enable some of the most challenging and time critical projects for our clients. This is why we were chosen as the Architect Engineer for ITER (International Thermonuclear Experimental Reactor), planned to be the world’s largest and most advanced experimental tokamak nuclear fusion reactor.

In 2014, Atkins acquired Nuclear Safety Associates (NSA), the US industry’s foremost authority for nuclear safety, regulatory compliance and licensing.

Our expertise

Atkins has more than 25 years of extensive experience and expertise within the USA and UK in the seismic qualification of a diverse range of structures and plants for nuclear and industrial facilities. We have leading technical experts in:

• Geotechnics• Finite element analysis• Code assessments• Seismic Qualification Utility Group (SQUG) seismic walkdown• Seismic probabilistic risk analysis (PRA)

In total we have more than 40 engineers with experience in seismic assessments and design. Atkins has engineers who are also qualified as SQUG Seismic Capability Engineers (SCE).

Our knowledge and experience of seismic qualification enables us to offer support with the following qualification methods:

• Site-Specific Probabilistic Seismic Hazard Analysis (PSHA) and Ground Motion Response Spectra (GMRS) development

• Seismic Equipment List Development• Seismic Walkdown Support and Training• Structure and Component Seismic Fragility Analysis• Seismic Plant Response Analysis• Model Development and Seismic PRA Quantification• Seismic Margins Analysis (EPRI or NRC method)• Development of Alternatives for Reducing Seismic Risk• Peer Certification Review Support• NRC Request for Additional Information (RAI) Support

Determining and justifying the response of structures and plant to seismic motion can be a complex problem. Atkins has experienced seismic engineers who ensure that the most appropriate methods are used, accurately evaluating seismic margins and improving the likelihood that the item can be qualified.

Seismic walkdowns should be carried out by SQUG-trained SCEs. Atkins has multiple SCEs with experience of working in the nuclear industry in both the commercial and the government sectors. These walkdown engineers are supported by more than 40 engineers with experience in seismic assessments and design.

We also provide industry-leading experience and knowledge in external event risk analyses using Probabilistic Risk Assessment (PRA) and have created and provided feedback on external event PRA methodologies and practices that have become industry standards. Our PRA analysts have developed leading edge software that efficiently and effectively supports seismic PRA analysis.

In addition to analysis, testing in the form of shake table tests may be necessary for a complex plant, especially if it needs to remain operational during and following a seismic event. Atkins can provide support to all aspects of the testing program, helping to accurately define motions and optimize the seismic capability of the plant.

Examples of seismic services to nuclear facilities

Our seismic and risk analysis experts have performed numerous tasks to support the nuclear industry in both the US and UK. Examples of our experience include:

• Seismic risk assessments for issues evaluated by the NRC’s Significance Determination Process (SDP).

• Delivery of PRA professional training courses including Seismic PRA and authoritative papers on external event analysis at PRA/PSA industry conferences.

• Seismic analysis for a fuel Fabrication Facility to satisfy NRC concerns from Fukushima.

• Seismic and structural engineering calculations using LSDYNA and ANSYS to calculate stresses due to seismic and impact loads to structures and components in the spent fuel loading bay area for numerous customers.

• Seismic walkdowns and analysis in conjunction with external events (seismic, wind, fire/explosions, flood, and aircraft crashes) for a Canadian Fuel Manufacturing Facility and Spent Fuel Storage Building.

• Seismic equipment qualification of the remote control room for the Advanced Test Reactor (ATR).

• Seismic structural assessments for a series of UK plants, analyzing the reactor buildings and turbine houses in terms of soil structure interaction effects, building response, displacement and acceleration time-histories, secondary response spectra and the integrity of the primary structure.

• Assessment of the effects of a postulated earthquake on reactor cores and their support structures, including consideration of possible post-elastic behavior of critical components. This work was carried out for a number of gas-cooled reactor cores, each of differing design.

• Seismic and geotechnical evaluations at TVA nuclear plants comprising soil dynamic seismic analyses and soil-structure interaction analyses for reactors, spent fuel pools, in-ground buried pipe and electrical conduit bank analyses. Support was also provided to evaluate the Ground Motion Response Spectrum (GMRS), and earthquake probability and risk analyses.

• The reinforced concrete design for the Spent Fuel Pools of an eastern US utility. Additional support was provided by evaluating the design of the switch gear and transformer buildings for standard design load cases including seismic and tornado wind, depressurization, and missiles.

• Seismic assessment of buildings at a power station in the UK as part of a periodic safety review. Detailed finite element models of the nuclear island buildings were used in the assessment of the structures to design codes. In-structure seismic motions were predicted for the assessment of essential plant items using a variety of techniques ranging from manual calculation to non-linear finite element analysis as appropriate.

• Review of the seismic safety case for a UK power station. This involved the identification of plant systems needed to achieve and maintain a safe shutdown condition, and detailed assessment of the plant equipment. Work included extensive site visits to walkdown and inspect the plant. This major assessment was documented in a Safety Case document, supported by a large number of plant-specific assessment reports, in a form suitable for presentation to the nuclear licensing authority.

• Seismic soil-structure interaction analyses and assessments have been carried out at a number of nuclear installations. A variety of one- and two-dimensional finite element computer modeling techniques have been applied.

• Seismic walkdowns and assessments based on SQUG procedures, client Seismic Guidelines, and EPRI procedures at multiple UK plants for the following plant and equipment:

- Piping - Fire fighting equipment - Ventilation systems - Breathing apparatus - Electrical cabinets - Cable raceways - Liquid oxygen tanks

For information about Atkins’ Seismic Capabilities contact:

Atkins

Nigel Thornton Director, Energy 5200 Seventy-Seven Center Drive Suite 500 Charlotte NC 28217 USA

Tel +1 704 522 7275 Cell +1 832 247 3330

Email: nigel.thornton@atkinsglobal.com

www.atkinsglobal.com