Nuclear Plants – Design for Operating and Special Load Cases, Decommissioning and Dismantling of Nuclear Power Plants, Interim Storage Facilities, and Repositories.

How do we generate the energy we need to live? The strategies of individual countries are very different in this respect: while some have already decided or realized to phase out nuclear power, others are building new plants. The demand for engineering services in nuclear plant engineering is correspondingly multifaceted:

New construction, conversion and retrofitting of nuclear power plants: design for operating and special load cases through computational simulation and measurement analysis

How to structurally secure nuclear power plants against earthquakes? This was one of the first questions addressed when the Wölfel Group was founded in 1971. Over more than 50 years, the topics of dynamics and strength have become our core competencies.


Based on many years of experience in the fields of calculated simulation and measurement data analysis, we deal with all structural, mechanical and electrotechnical aspects of nuclear power plants. In addition to the load cases of normal operation, special load cases, such as earthquake, explosion pressure wave and airplane crash are included in our scope of services. For this we work in accordance with national and international standards.

Our service portfolio in the area of nuclear power plants:

  • Calculated proof based on modeling appropriate for the particular load cases and requirements (linear and non-linear bar, shell or volume models)
  • Dynamic calculation using static calibration tests, spectral methods, time history analyses or probabilistic procedures
  • Calculation of response spectra taking into account the interaction between ground and building
  • Verification of the load carrying capacity and usability of buildings and components made of reinforced concrete, pretensioned concrete, steel, and masonry
  • Load carrying capacity (stability under load), integrity and functional capability of mechanical and electrical parts of the plant, based on
    • calculated proof,
    • experimental proof,
    • analogy proof (similarity) or
    • plausibility tests (experience-based)
  • Re-evaluation of existing structural and mechanical parts of the plant when requirements have been changed
  • Submission of proposals for the strengthening and retrofitting of existing plants
  • Inspection of existing plants in the presence of experienced experts
  • Preliminary review and quality assurance of design documents submitted by third parties for the plant operator
  • Preparation of testable and quality-assured documentation of all operations and results according to national and international requirements (KTA, NQA-1)
  • Support in technical discussions with contractors, experts and authorities

Static monitoring of dismantling nuclear power plants

For several years we have been active on behalf of plant operators regarding the dismantling of nuclear plants.

We develop dismantling concepts, from feasibility studies through to the auditable implementation design, and assist you in the individual phases of dismantling, with adaptation of the proceedings to the changed requirements and potential hazard compared to the ongoing operation.

A special challenge: strength analysis in the dismantling of nuclear plants

Our experience shows that stress analyses in dismantling often are no standard analyses. Engineering assessments therefore have a high status, as they consider the following points:

  • Design, material and analyses date back to the date of their generation, whereas the analyses for the dismantling are to be performed according to the rules and regulations currently valid and applicable.

  • Full documentation of the status „as is“ partly is difficult to procure; often a comparison of the “as-built” documentation with the “as-is” structure is required.

  • Rules and regulations have been issued for the design and construction of new structures, but not for the dismantling of existing ones.

Our service portfolio in the area of decommissioning and dismantling:

  • Development and definition of dismantling steps
  • Development of analysis concepts
  • Review and assessment of „as-built” documentation
  • Assessment of the load-bearing capacity by means of a mechanical analysis from various points of load application
  • Development and design of supporting and auxiliary structures
  • Design of new installations in the existing building structure
  • Development of special design constructions and solutions
  • Special load cases as e.g. “crash of components”
  • Support in technical discussions with experts and licensing authorities

Design and calculation as part of the approval procedures for interim and repositories

When it comes to the interim and final storage facilities for radioactive waste, strict safety requirements have to be met. Before commissioning, numerous calculations and designs are necessary within the approval procedures.

Our service portfolio in the area of interim storage facilities and repositories:

  • Computational analyses of structural and mechanical components for all load cases of normal operation and for special load cases such as e.g. earthquake, pressure wave and airplane crash
  • Analysis of response spectra for the design of containers, vessels and indoor cranes
  • Static and nonlinear dynamic analysis of vessel stacks
  • Analysis of the structural stability and integrity of the container stacks

Permanent protection of your plant through earthquake monitoring

Using seismic instrumentation, earthquake occurrences can be detected immediately and reliably, which in turn makes it possible to implement protective measures very quickly.

>> Learn more about our service portfolio in the area of seismic instrumentation

Operating and special loads: our areas of expertise


Whether in the context of new constructions, conversions or retrofits: we support plant manufacturers and operators in the design of entire plants or individual components in all structural-mechanical issues. Due to our expertise built up over many years, we are particularly consulted for the following load cases:

Please contact me personally


I will be happy to advise you on questions concerning the design of plants and components for operational and special loads.

Dr.-Ing. Marcus Ries

+49 931 49708-370
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Mechanical Engineering, TU Darmstadt

Acadamic Degree

Dipl.-Ing. / Dr.-Ing